5870 Bottleneck Investigation (CPU and/or Memory Bandwidth)

I don't expect to have my card until Friday at the earliest ( figures the Asus are in stock now but I'll wait for the XFX... ) but if anyone has a request of a game / test run that they feel might serve as a good comparison let me know and I'll try to set it up now ( I have the majority of the bigger games over the last 2 years so just hit me up with a PM and If it is something that is easy enough to compare, I'll do some clock scaling ) I want to do it at 1920x1200 with 8x Adaptive AA and also with no AA so there is that contrast ( obviously 8x MSAA uses more bandwidth / vram ) I don't see the point in testing at lower resolutions personally.

From what I've see so far here and elsewhere though clocks don't seem to scale any more than past designs so it is tough to say what is holding it back. I'm still a tad disappointed that the 4870x2 pulls ahead in as many things as it does. Multigpu has gotten better yes really...

Quote:

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Originally Posted by Chumbucket843

it depends on the what it is doing .you can see here Ati is the intel of synthetic benchmarks.http://www.bit-tech.net/hardware/gra...ture-review/10. the wider you make a vector, the harder it is to keep under full load.

on average one flop takes 1 byte per second of memory performance. this translates to 2 terabytes per second of required bandwidth for rv870 so every gpu made is bottlenecked from this. the only way is to further reduce the memory operation to calculation ratio. its already 100:1 but it must go higher.

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thats too much theory there if you ask me...
this bw/flop number is a guideline... just think about it for a second, according to that guideline applied as a RULE, every gpu with the same flop performance would require the same memory bandwidth... which is clearly not true... as a guideline it may work very well, but even then it depends so much on what your actually doing and how much or how little data repetition your facing and how well you can group instructions that use the same data, and how many instructions use data that a previous instruction has just created inside the gpu, in a register or in cache, so it never needs to load any data from memory etc etc etc... ;)

as a rough guideline it works, but its not a rule :)

the anandtech review is very interesting...
so basically a 5850 with 2 less simd units and 15% lower clocks performs 10-15% worse than a 5870...
that means a 5850 at 5870 speeds will most likely perform so similar to it that you might not be able to tell the diference...
maybe there will be fake 5870s in china which are actually 5850s :lol:

I do not think the 5870 is bandwidth limited at all. There are many examples out there, and in this very thread, showing that 10%-12% increases in memory bandwidth is not increasing frame rates that much (1.5% - 3%). This small increase in frame rate is due to the lowering of the memory timings and not the increase in memory bandwidth. The same phenomenon happens when overclocking system memory. This benchmark shows that 10% increases in core speed is translating to a 5.5% increase in frame rate, where as the same 10% increase in memory bandwidth only increases frame rates by 1.5%.

You guys are getting marginal increases in frame rates when bumping up the memory speeds from the decrease in GDDR5 memory timings, and you're confusing that with a memory bottleneck.

5870 AF performance:

http://www.bit-tech.net/hardware/gra...re-analysis/12

Looks like there huge performance drop enabling 16xAF.

Interesting, so currently ATI have better anti aliasing scaling but still have inferior AF scaling. I expect GT300 to both have good AF scaling and AA performance so it shall be interesting. I just installed the card so I'll have to see what the deal is as far as AF quality ( as 5 series AF is supposed to be the highest quality or so we are told )

I hope someone makes a tool that works with the memory error correction (as in it can detect errors ) as that would make overclokng much simpler. If anyone has any clock requests ( eg at less than stock ) Please let me know and I'll do some testing over the weekend.

Quote:

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Originally Posted by Kuntz

You guys are getting marginal increases in frame rates when bumping up the memory speeds from the decrease in GDDR5 memory timings, and you're confusing that with a memory bottleneck.

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your saying that performance increases minimally because the mem timings get adjusted automatically to the higher memory speeds...

but what do you mean with people confuse that with a memory bottleneck?

a memory bottleneck indication would be if performance WOULD increase when ocing the memory, not when ocing memory barely does anything at all, like in this case...

and yes, the timings get adjusted automatically on ati cards, on nv cards as well afaik... but the increase in timings is not linear, so higher mem clocks still increase the bandwidth even though timings get increased.

Quote:

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Originally Posted by saaya

your saying that performance increases minimally because the mem timings get adjusted automatically to the higher memory speeds...

but what do you mean with people confuse that with a memory bottleneck?

a memory bottleneck indication would be if performance WOULD increase when ocing the memory, not when ocing memory barely does anything at all, like in this case...

and yes, the timings get adjusted automatically on ati cards, on nv cards as well afaik... but the increase in timings is not linear, so higher mem clocks still increase the bandwidth even though timings get increased.

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i do have an idealistic view on memory bandwidth but obviously you would have to consider some things require a lot of bandwidth. in games AA, AF, fillrates are bandwidth intensive. in gpgpu the bottleneck will usually be bandwidth. transcoding is a good example of this. fortunately some things dont have that problem, like perlin noise which loves vectors or texture sampling. i think it caches really well too.

Quote:

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Originally Posted by saaya

your saying that performance increases minimally because the mem timings get adjusted automatically to the higher memory speeds...

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No, I think the memory timings are static, they do not change with memory adjustment. So if they are at, for example, a total cycle delay of 10, that would mean:

10 cycles @ 1200MHz = 8.3ns delay
10 cycles @ 1300MHz = 7.7ns delay

Because there is no memory bottleneck on the 5870 cards, when you increase the memory speed, all you are really doing is decreasing the nanosecond delay on memory operations, which is why a 10% increase in memory speed is only getting a 1.5% increase in performance.

Quote:

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Originally Posted by Kuntz

No, I think the memory timings are static, they do not change with memory adjustment. So if they are at, for example, a total cycle delay of 10, that would mean:

10 cycles @ 1200MHz = 8.3ns delay
10 cycles @ 1300MHz = 7.7ns delay

Because there is no memory bottleneck on the 5870 cards, when you increase the memory speed, all you are really doing is decreasing the nanosecond delay on memory operations, which is why a 10% increase in memory speed is only getting a 1.5% increase in performance.

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How would you explain all these performance increases from memory overclocking that are greater than 1.5% per 100mhz?

Quote:

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Originally Posted by jaredpace

850 / 3600 / 091.7 / 0 / 0%
850 / 4000 / 095.2 / +3.5 +3.8%
850 / 4400 / 097.9 / +2.7 +2.9%
850 / 4800 / 100.3 / +2.5 +2.5%
850 / 5200 / 102.4 / +2.1 +2.1%

850 / 4400 - 40,9 - 0 / 0%
850 / 4800 - 42,0 - +1.1 +2.7%
850 / 5200 - 43,1 - +1.1 +2.6%

785 / 4400 - 39,3 - 0 / 0%
850 / 4800 - 42,0 - +2.7 +6.9%
900 / 5200 - 44,7 - +2.7 +6.4%

850 / 4800 - 31.6 - 0 / 0%
850 / 5272 - 32.3 - +0.6 +2.2%

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And this?
http://www.firingsquad.com/hardware/...es/bat1920.gif
http://www.firingsquad.com/hardware/...ing/page10.asp

Is this because of the latency of the memory (in nanoseconds), and not due to increasing bandwidth for chip's computational throughput?

Quote:

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Originally Posted by jaredpace

How would you explain all these performance increases from memory overclocking that are greater than 1.5% per 100mhz?

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I've already explained them, they fall under the same explanation.

Quote:

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Originally Posted by jaredpace

http://www.firingsquad.com/hardware/...es/bat1920.gif
http://www.firingsquad.com/hardware/...ing/page10.asp

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2.9% perf increase from 9.8% memory speed increase.

Code:

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850 / 4800 / 100.3 / +2.5 +2.5%
850 / 5200 / 102.4 / +2.1 +2.1%

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2.1% perf increase from 8.3% memory speed increase.


I'll summurize the entire article in per cent's. Each game has 3 graphs for it representing various resolutions and stuff. Each overclock was by 9.8%:

Call of Duty WaW:
-1.3%
-0.7%
-2.0%

Crysis:
-2.2%
-2.2%
-0.3%

Crysis Very High:
-2.1%
-2.2%
-1.0%

Far Cry 2:
-2.3%
-2.4%
-2.3%

Stalker Clear Sky:
-0.5%
-0.8%
-1.6%

Left 4 Dead:
-0.8%
-2.0%
-2.9%

Res Evil 5:
-1.4%
-2.0%
-2.2%

Batman:
-3.3%
-2.9%
-3.9%

HAWX:
-1.2%
-2.7%
-3.6%

The evidence is pretty clear to me, the 5870 has no memory bottleneck. There is no increase in frame rates from increasing the memory bandwidth. These marginal increases are just from the decrease in memory timings.

I am no expert, this is just my opinion & conclusion based on the evidence floating around the internet.

If ATI went with a 512-bit bus, or 384-bit like nVidia, this would have increased memory bandwidth, however memory timings would remain the same on the GDD5 IC's, thus there would be no performance increase from the increased bus width. The cost of the card would be astronomical compared to it's entry price of $379, and it would be all for a 0% performanec increase.

if one of you guys has a 5870 do the same thing i did.

this is furmark at 1280x1024 8xAA 16xAF on a gtx 260 192.
all clocks but memory are the same. i want to see how the regression for the 5870 compares. i know its a little ghetto but i dont care. the memory clocks are on the bottom
http://img194.imageshack.us/img194/417/furmemaa.jpg

Here you go.

Furmark 1.7
1280x1024 8x AA 60000MS
HD 5870 1GB

Mem - Score

1300 - 2733

1200 - 2537

1100 - 2360

1000 - 2187

900 - 1963

http://img194.imageshack.us/img194/9013/graphtv.jpg



I used what CCC offers for memory range.

I noticed a weird thing though. When Overdrive is enabled the gpu 2d clocks are 157 / 300 but when it is not enabled they are 400 / 1200. This is really strange. Also I suffer from the flickering display issue on the monitor connected to the second DVI port when over drive is enabled. Its fine for benching but too annoying to be usable for games. I'm sure it will be fixed soon though.

EDIT : I discovered that the correct 2d power play clocks are in fact 157 / 300. HOWEVER due to the timing differences when using more than 1 display the lowest they go is 400/1200. In other words so much for 27watt idle with more than one display :( Realistically I don't really care that much, I'll take a second display over a few watts any day. It is still an issue however as you are unable to properly overclock when using more than 1 display as it stands. I'm glad I've found this out as no reviews I've seen mention it ( as most reviews use 1 24-30" display ) I'd be fine with the same 400/1200 clocks at idle if it meant the display wouldn't flicker.

Nice test chickenfeed. SO the 5870 CAN use all the bandwidth you can give it. It's scaling almost linearly.

Yeah seems to be the case.

I tried doing a work around for the monitor flickering issue with overdrive enabled by setting custom clock states in a profile but sadly the memory still idles at 300 regardless of the setting in the profile meaning that I can't overclock with more than 1 display. I am going to use my 20" for the time being ( my 24" has image retention so I'm going to let it take a break for a week or so )

I will do some further testing with furmark with the gpu clock as well and gpu / memory combined. I am going to do the tests at 3 resolutions to give us the full picture as well.

Quote:

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Originally Posted by Chickenfeed

Interesting, so currently ATI have better anti aliasing scaling but still have inferior AF scaling.

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This is true, but you have to take into account that AF quality is superior on the 5800 series aswell..

Quote:

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Originally Posted by jaredpace

Nice test chickenfeed. SO the 5870 CAN use all the bandwidth you can give it. It's scaling almost linearly.

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or the test is simply bandwidth starved.I used to get 100 more fps by overcloking memory on my 3870 in the ati tool window,made no difference in games.

Quote:

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Originally Posted by gamervivek

or the test is simply bandwidth starved.I used to get 100 more fps by overcloking memory on my 3870 in the ati tool window,made no difference in games.

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yeah good point. all we're really looking for is fps increase in games. firing squad already proved that for us.

What may also be possible is that the card may be intentionally detuned or purposely not optimized. Given that ATI has played it's hand much earlier than NVidia, it wouldn't surprise me if ATI left some performance potential in reserve to counter NVidia. This would give Nvidia the illusion that the 5870 is weaker than it is.

Just a thought...:)

I did the same test again but this time I left memory stock and changed the core speed from 600-900 in 50Mhz increments.

Furmark 1.7
1280x1024 8x AA 60000MS
HD 5870 1GB

Core - Score

900 - 2555

850 - 2551

800 - 2539

750 - 2531

700 - 2527

650 - 2524

600 - 2115

http://img9.imageshack.us/img9/5492/grapho.jpg

What is interesting is that from 650-900 performance barely changes. However at 600 it takes a considerable dive.

Because this is a relatively low resolution I am going to redo do both these tests also at 1680x1050 and 1920x1200 over the weekend. Perhaps there will be more gains on core increase at those resolutions but if 1280x1024 was any indication, I'll assume Furmark likes memory bandwidth over anything.

If I get really bored I might do Vantage ( although it would take a full day to properly do :ROTF: ; I'll probaley just run the GPU tests on Extreme and only look at the GPU score and avgs ) I am trying to pick out some games that are easily benched to do similar tests as well. I'll most likely do Far Cry 2 at the very least as its built in bench tool makes life oh so easy and it is also a recent and stressful enough game to actually show any scaling.

By the way I made the graphs at : http://nces.ed.gov/nceskids/createAgraph/default.aspx. Google searches FTW and LOL at kids zone.

the 5870 is most definitly bandwidth starved imo, I just dont see the (approx) 153GB/s (?) being enough..

I suspect the refresh, 5890?, will have much faster mem and a slight bump in core speed with a huge performance gain.

I think ATi may have slightly gimped the 5870 on purpose to get more life out of the 5800 series with future revisions..

i went with texture filtering on high because ATi said that the 5870 is bandwidth limited 50% of the time.

ROUND 2: crysis demo benchmark
0x AA 0x AF
all settings on very high. gtx 260
http://img39.imageshack.us/img39/6995/crysisbecnh.jpg
framerates were MUCH smoother with memory at full speed, something you have to see to believe. a 100% increase in bandwidth gained 30% speed and much smoother fps. this should be interesting.

Quote:

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Originally Posted by Chumbucket843

i went with texture filtering on high because ATi said that the 5870 is bandwidth limited 50% of the time.

ROUND 2: crysis demo benchmark
0x AA 0x AF
all settings on very high.
http://img39.imageshack.us/img39/6995/crysisbecnh.jpg
framerates were MUCH smoother with memory at full speed, something you have to see to believe. a 100% increase in bandwidth gained 30% speed and much smoother fps. this should be interesting.

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You increased memory speed by 15% (1000 -> 1150) and frame rate only went up 3.4% (29 -> 30). That is not from the increased bandwidth, that is from the decrease in memory latency.

Quote:

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Originally Posted by Kuntz

You increased memory speed by 15% (1000 -> 1500) and frame rate only went up 3.4% (29 -> 30). That is not from the increased bandwidth, that is from the decrease in memory latency.

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went from 550mhz to 1150 mhz. i wish my memory went to 1500mhz:rolleyes:. the frame rate went from 23.6 to 29.7. gpu's are designed to hide latency. my card can handle 24,576 threads so any time spent accessing memory is covered up by working on other threads. this wasnt meant to be memory intensive at all. nobody buys a high end card and not use any texture filtering. it might be memory size too. double the shaders, double the memory needed for all of those alu's. its kind of like a 4870 512mb.

I agree with kuntz. Furmark is a nice tool but its not a game test. You dont know what it does and why the memory scales well there. If a card really is starved and you overclock the memory 10% you would see a 9-10% boost in performance. In games thats not the case. It seems to be the case in furmark but like i said its not a game test. That kind of load will not happen in games. Its to fully stress the VGA card to see if its stable. The load si way higher then any game on the market. So yes there are situations where there is not enough bandwith vor the RV870 core. But thats not the reason why is current Game performance is a bit to low for our liking.

Quote:

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Originally Posted by Chumbucket843

went from 550mhz to 1150 mhz. i wish my memory went to 1500mhz:rolleyes:. the frame rate went from 23.6 to 29.7. gpu's are designed to hide latency. my card can handle 24,576 threads so any time spent accessing memory is covered up by working on other threads. this wasnt meant to be memory intensive at all. nobody buys a high end card and not use any texture filtering. it might be memory size too. double the shaders, double the memory needed for all of those alu's. its kind of like a 4870 512mb.

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You could be right about the memory. The HD4870 gained a lot but the HD4850 did not gain much by going from 512 to 1024mb. I have also seen it in the past with the Radeon 8500. the 128 mb version was a lot faster then the 64 mb version while the clocks where the same.

It could be the same problem here but personally i dont think that is the case. If its the case we could see 10-25% performance gains from the 2 GB version. We will know it when it comes out in 3-4 weeks.

Quote:

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Originally Posted by Kuntz

No, I think the memory timings are static, they do not change with memory adjustment. So if they are at, for example, a total cycle delay of 10, that would mean:

10 cycles @ 1200MHz = 8.3ns delay
10 cycles @ 1300MHz = 7.7ns delay

Because there is no memory bottleneck on the 5870 cards, when you increase the memory speed, all you are really doing is decreasing the nanosecond delay on memory operations, which is why a 10% increase in memory speed is only getting a 1.5% increase in performance.

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rv600 and rv670 and rv770 all adjusted the timings when you overclocked the memory... id be surprised if rv870 doesnt do it anymore...

a drop from 8.3 to 7.7ns is a latency reduction of 7% though, then how come we still only get a 1.5% boost? and memory timings tend to not really matter on vgas, they need bw bw bw... they usually have cas15 or so...

i dont think the boost we see is only from reduced memory latency, as a matter of fact, i dont think memory latency decreases a lot, since r600 all gpus use a formula to calculate memory timings based on memory clock. the latency still decreases, and bw still increases, otherwise we wouldnt see any gains at all, but its less than we would see from a static timing config with increased memory speed.

you are probably thinking of system memory performing better with lower timings, for vgas that doesnt apply... they do score better with lower timings by the boost is tiny compared to cpu system memory...

nice tests chumbucket and chickenfield (sp?) :D
what it shows is that in furmark the 5870 def is bw limited, but that doesnt seem to be the case in actual games...
furmark is 99% shader heavy load only isnt it?

Furmark has a strange way of stressing the cards to there max. You can overheat a HD4870 or HD4890 at ease even without renaming the .exe file A twin turbo could not cool a HD4890 VRM's got to hot. Stock cooler does a better job there bot you do have a lot more noise. The power draw is also way higher. So its deffinatly doing something. I also think furmark is able to keep all the 800 (RV770 and RV790) and 1600 shaders (RV870) fully loaded where games can not.

i dont think its that all the shader cores are loaded, games can def do that, what furmark does is load the cores completely, all 5 parts of it, and occt even feeds the rest of the logic with work and keeps texture and geometry setup busy with bogus work i think... its kinda like linx that bombards cpus with random instructions without any dependencies so every single unit is fully loaded. i think... :D

Quote:

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Originally Posted by saaya

i dont think its that all the shader cores are loaded, games can def do that, what furmark does is load the cores completely, all 5 parts of it, and occt even feeds the rest of the logic with work and keeps texture and geometry setup busy with bogus work i think... its kinda like linx that bombards cpus with random instructions without any dependencies so every single unit is fully loaded. i think... :D

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Indeed thats what i tried to say :P Games mostly load 2-4 out of 5 alu's. And sometimes they get up to 5.

Quote:

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Originally Posted by Chickenfeed

Furmark 1.7
1280x1024 8x AA 60000MS
HD 5870 1GB

Mem - Score
1300 - 2733
1200 - 2537
1100 - 2360
1000 - 2187
900 - 1963

http://img194.imageshack.us/img194/9013/graphtv.jpg

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My HD4890 at SXGA, 8xMSAA scored 1694 at core 850MHz, memory 900MHz and 1859 at memory 1000MHz. So HD5870 at same clocks is whopping 16-17% faster. And that, ladies and gentlemen, is nothing short of messed up considering Cypress' overwhelming HW level superiority and the fact Furmark is very, very shader dependant...

Any conspiracy theories yet?

Witholding performance via driver for GT300 launch? lol...

Quote:

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Originally Posted by largon

My HD4890 at SXGA, 8xMSAA scored 1694 at core 850MHz, memory 900MHz and 1859 at memory 1000MHz. So HD5870 at same clocks is whopping 16-17% faster. And that, ladies and gentlemen, is nothing short of messed up considering Cypress' overwhelming HW level superiority and the fact Furmark is very, very shader dependant...

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doesn't furmark have to be updated for better loading of newer cards?

Quote:

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Originally Posted by Miwo

Any conspiracy theories yet?

Witholding performance via driver for GT300 launch? lol...

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Well we haven't seen what the x2 can do yet. It's always possible that they've figured out an more efficient way for the GPU's to work over the traditional cfx..

wild speculations :)

gamervivek,
Of course not. It's just an OpenGL benchmark app. It's not like games and all 3D aps need to be patched to "support" new HW.
:stick:

Quote:

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Originally Posted by largon

My HD4890 at SXGA, 8xMSAA scored 1694 at core 850MHz, memory 900MHz and 1859 at memory 1000MHz. So HD5870 at same clocks is whopping 16-17% faster. And that, ladies and gentlemen, is nothing short of messed up considering Cypress' overwhelming HW level superiority and the fact Furmark is very, very shader dependant...

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I will be doing this test at more "real" world resolutions soon ( real world as far as these cards go - I know 1280x1024 is still widely used though ) I do agree that something is pretty messed up given the small difference.

I'll mention I've found that I get a display driver has stopped running error at 900/1300 when running OCCTs furmark type test after 30-45min ( this got core to like 88C and fan to over 50% which gets quite loud ) With actual games though it usually is in the 70s and only Crysis has managed to get any higher. I'm not sure if this is an indication of the card not being able to handle the load at these clocks in something like Furmark or merely drivers in their infancy. All I know is no games or other programs have shown signs of issue yet so far.

Quote:

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Originally Posted by saaya

rv600 and rv670 and rv770 all adjusted the timings when you overclocked the memory... id be surprised if rv870 doesnt do it anymore...

a drop from 8.3 to 7.7ns is a latency reduction of 7% though, then how come we still only get a 1.5% boost? and memory timings tend to not really matter on vgas, they need bw bw bw... they usually have cas15 or so...

i dont think the boost we see is only from reduced memory latency, as a matter of fact, i dont think memory latency decreases a lot, since r600 all gpus use a formula to calculate memory timings based on memory clock. the latency still decreases, and bw still increases, otherwise we wouldnt see any gains at all, but its less than we would see from a static timing config with increased memory speed.

you are probably thinking of system memory performing better with lower timings, for vgas that doesnt apply... they do score better with lower timings by the boost is tiny compared to cpu system memory...

nice tests chumbucket and chickenfield (sp?) :D
what it shows is that in furmark the 5870 def is bw limited, but that doesnt seem to be the case in actual games...
furmark is 99% shader heavy load only isnt it?

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Ah I never knew that about the memory timings on ATI's cards.

I still don't think we have a memory bandwidth issue in games.

If a core increase of 10% nets 5% on average, and a memory bandwidth increase only nets 0.5% to 3.5%, I'd say we have a core bottleneck more than anything. :p

Though this benchmark stands out for oddity:

http://www.firingsquad.com/hardware/...ages/c2560.gif

-A 10% increase in memory nets ... 0% increase in frame rate.
-A 10% increase in core nets ... 0.6% increase in frame rate.
-Both increases combined and now we have a 7.4% increase in frame rate.

Quote:

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Originally Posted by saaya

i dont think its that all the shader cores are loaded, games can def do that, what furmark does is load the cores completely, all 5 parts of it, and occt even feeds the rest of the logic with work and keeps texture and geometry setup busy with bogus work i think... its kinda like linx that bombards cpus with random instructions without any dependencies so every single unit is fully loaded. i think... :D

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its more complicated than that. if a shader program is flow heavy it will do a lot better on nvidia cards. loading all of the alu's is harder than it sounds. its vliw too so not all instructions can take full advantage of all of the shaders. they encourage programmers to use certain floats and vecs to get the fastest performance. memory size is probably the issue. think about it. if you double the amount of threads you double the required memory. its like having a 4870 512mb. it makes sense that seeing that they doubled everything but memory and bandwidth.

Quote:

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Originally Posted by Miwo

Any conspiracy theories yet?

Witholding performance via driver for GT300 launch? lol...

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Im still waiting for this "investigation" to be finalised so we can see how ATi have completely stuffed the HD5870 :rofl:

Quote:

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Originally Posted by Miwo

Any conspiracy theories yet?

Witholding performance via driver for GT300 launch? lol...

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I know that's what's on my mind. I tried asking on Terry Makedon's (CatalystMaker) twitter, but he only evaded the question, then stopped answering when I pushed harder. I'm really beginning to think they're holding the card back.

One theory why 5870 is slower than its spec suggest: Its 1600 shaders are nowhere near working at their max capacity. This would explain why

1) increasing memory clocks does not improve results as much as expected.
2) load power is lower than other cards in games but much higher in occt.
3) raising memory has a greater effect in furmark

"if" they can hold it back a little, it make sense as they wait for the late and very late g300 performances.

You know, ATI holding the card back really goes pretty far into tinfoil hat territory, but it almost makes sense...

I think it might be accidentally held back due to drivers. If I understand it correctly, a lot of the performance from ATI's design comes from the GPU being fed information optimally. I'd wait for a few driver releases to see final performance numbers.

Yep, need better drivers, hard to expect some crappy release candidate version to offer 100% performance. :yepp:

I think its driver related but i dont think AMD does this in purpose. Because the card now looks bad vs the HD4870 X2. The X2 is out gunning it. They did change a lot in the core. So i expect they will be able to boost the performance by 10-20% in the future. We have also seen massive gains with newer drivers for the HD48xx cards.

And about furmark. I know AMD does something in there drivers to cut down the load on the GFX card. Furmark puts a rare load on the card causing some to overheat. Because of that AMD has put a limiter in the driver. You can disable it by renaming the .exe in something else. You might wanna try that if you want a fair compare. But keep an eye out for you temperatures. They can get higher then before !

So despite what they claimed the new AF does take more serious hit than before:

http://pclab.pl/art38674-9.html

Might be a better idea to run these cards at 8xAF instead of 16x

Quote:

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Originally Posted by saaya

rv600 and rv670 and rv770 all adjusted the timings when you overclocked the memory... id be surprised if rv870 doesnt do it anymore...

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That's very interesting, I remember reading that before somewhere. Don't suppose you have a link?

Maybe a bottleneck in crossfire.

http://www.hardwarezone.com/articles...?cid=3&id=3032

Quote:

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Originally Posted by saaya

... its kinda like linx that bombards cpus with random instructions without any dependencies so every single unit is fully loaded. i think... :D

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Sry but linx is nothing more then a gui for linpack... :rolleyes:

http://www.xtremesystems.org/forums/...=235831&page=2

look at the score on the pages before oc on card and after.
seems more like a bios problem, note this was an AMD system though :shrug:

Quote:

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Originally Posted by JimmyH

One theory why 5870 is slower than its spec suggest: Its 1600 shaders are nowhere near working at their max capacity. This would explain why

1) increasing memory clocks does not improve results as much as expected.
2) load power is lower than other cards in games but much higher in occt.
3) raising memory has a greater effect in furmark

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If you want to verify the capacities of the ALUs you should consider testing the same stuff on the "Froblin"-demo with a 4870 and a 5870, because you got adaptive tessalation even without DX11.
That somewhat disconnects the internal from the external bandwidth requirements, as no (proportionally) more geometry is streamed into the processor.
I would also make the very vague guess that crunching on up-LODed geometry creates a somewhat shaderinstruction-grouping favoring situation. But that's very hard to say. That can really only be verified if you can play around with the LOD-strength in the demo.

You'd check something like this combinations:

LOD: 1, 2, 4
Chips: 4870, 5870
Core-Clock: x, y, z

BTW the architecture is well described (ATI published ta 392 page doc to the linux guys), so someone eager may find the reason in there.

Good luck

http://img.techpowerup.org/091116/wolf5.jpg

Unigine Heaven Benchmark - 1680x1050 - 4xAA, 16xAF - max w/tesselation - Cat 9.10

650/900 = 23.9 fps
650/950 = 24.4 fps
650/1000 = 24.7 fps
650/1050 = 24.9 fps
650/1100 = 25.1 fps
650/1150 = 25.2 fps
650/1200 = 25.5 fps
650/1250 = 25.7 fps
650/1300 = 25.8 fps

725/900 = 26.0 fps
725/950 = 26.2 fps
725/1000 = 26.7 fps
725/1050 = 27.0 fps
725/1100 = 27.3 fps
725/1150 = 27.4 fps
725/1200 = 27.8 fps
725/1250 = 28.0 fps
725/1300 = 28.2 fps

800/900 = 27.7 fps
800/950 = 28.2 fps
800/1000 = 28.6 fps
800/1050 = 28.9 fps
800/1100 = 29.3 fps
800/1150 = 29.6 fps
800/1200 = 29.8 fps
800/1250 = 30.1 fps
800/1300 = 30.4 fps

875/900 = 29.4 fps
875/950 = 29.9 fps
875/1000 = 30.2 fps
875/1050 = 30.7 fps
875/1100 = 31.1 fps
875/1150 = 31.4 fps
875/1200 = 31.8 fps
875/1250 = 32.1 fps
875/1300 = 32.4 fps

950/900 = 30.7 fps
950/950 = 31.1 fps
950/1000 = 31.7 fps
950/1050 = 32.1 fps
950/1100 = 32.6 fps
950/1150 = 33.3 fps
950/1200 = 33.6 fps
950/1250 = 33.8 fps
950/1300 = 34.4 fps

mem vs core

900/650 = 23.9 fps
900/725 = 26.0 fps
900/800 = 27.7 fps
900/875 = 29.4 fps
900/950 = 30.7 fps

950/650 = 24.4 fps
950/725 = 26.2 fps
950/800 = 28.2 fps
950/875 = 29.9 fps
950/950 = 31.1 fps

1000/650 = 24.7 fps
1000/725 = 26.7 fps
1000/800 = 28.6 fps
1000/875 = 30.2 fps
1000/950 = 31.7 fps

1050/650 = 24.9 fps
1050/725 = 27.0 fps
1050/800 = 28.9 fps
1050/875 = 30.7 fps
1050/950 = 32.1 fps

1100/650 = 25.1 fps
1100/725 = 27.3 fps
1100/800 = 29.3 fps
1100/875 = 31.1 fps
1100/950 = 32.6 fps

1150/650 = 25.2 fps
1150/725 = 27.4 fps
1150/800 = 29.6 fps
1150/875 = 31.4 fps
1150/950 = 33.3 fps

1200/650 = 25.5 fps
1200/725 = 27.8 fps
1200/800 = 29.8 fps
1200/875 = 31.8 fps
1200/950 = 33.6 fps

1250/650 = 25.7 fps
1250/725 = 28.0 fps
1250/800 = 30.1 fps
1250/875 = 32.1 fps
1250/950 = 33.8 fps

1300/650 = 25.8 fps
1300/725 = 28.2 fps
1300/800 = 30.4 fps
1300/875 = 32.4 fps
1300/950 = 34.4 fps

http://forums.techpowerup.com/showth...106814&page=15

I think this says compute power @ core of 650mhz gets a good increase as memory bandwidth increases. Also, quite interestingly, as compute power of the core increases towards 1000mhz, the performance increase associated with the memory bandwidth increase becomes greater itself. (degree of performance increases as well!).

Strange idea:

Anyone tried changing the PCI-E mhz anything and see if it affects the performance?:D

Quote:

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Originally Posted by Smartidiot89

Strange idea:

Anyone tried changing the PCI-E mhz anything and see if it affects the performance?:D

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I got a small performance boost from raising the PCI-E from 100 to 115MHz when I used my 285GTX, but I get no gain when I change it with my 5850's.

Quote:

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Originally Posted by Kuntz

No, I think the memory timings are static, they do not change with memory adjustment. So if they are at, for example, a total cycle delay of 10, that would mean:

10 cycles @ 1200MHz = 8.3ns delay
10 cycles @ 1300MHz = 7.7ns delay

Because there is no memory bottleneck on the 5870 cards, when you increase the memory speed, all you are really doing is decreasing the nanosecond delay on memory operations, which is why a 10% increase in memory speed is only getting a 1.5% increase in performance.

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Here is good table of specification comparison of GDDR3, GDDR4 and GDDR5.
http://theovalich.wordpress.com/2008...45-diferences/

1. GDDR5 has high latency and so Fermi/Cypress have lots of cache/buffers. Unless special ultra high resolution with very large texturing benchmark is used, the mem system isn't CONSTANTLY used.

2. Although higher mem clock does marginally improve performance, maybe because offset by increasing errors.

3. Remember the i7/Phenom "un-core" clock. You only see significant mem scaling when you also increase the GPU clock... perhaps because this is increasing the mem controller speed and cache. ie doesn't help speeding up getting data to the chip, when the chip is slower and takes time carrying data where needed.

4. Driver optimizations have far greater impact than ALL OTHER FACTORS COMBINED. A well tuned shader compiler which makes good use of registers and cache can make minimal use of memory bandwidth - of course the behaviour would be different for other vendors/cards.

5. Issue of PCB quality (impedance matching), clock skew, and training. At super crazy high 5 000 000 000 bits per second GDDR5 is certainly not CAS3 or much higher than CAS9. The 8 bit prefetch latency is probably big factor. overriding factor.

Quote:

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Originally Posted by hurleybird

Got my 5870 today, but I can't seem to get the GPUclock utility to work. I'm using the RC7 drivers leaked from MSI, maybe that's the problem...

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maybe try the 8.663.1_Beta5_Hemlock_VistaWin7_Nov11 and see if it will help. they are the drivers i am using now on vista and win7 right now.

and so far so good and they run better then the official 9.11 did. since they cause some shader problems in borderlands for me.

but the 9.12 betas fix that for me.

but for me i have not over clocked my 5870 yet since i have no clue of how or what to do.

and from what i have read in this forum i really do not want to since this is my 1st rma 5870.

since my 5870 came to me bad and now this 1 seems to be ok

http://www.filefront.com/15115547/8....Win7_Nov11.exe

Even though this IS xtremesystems, I dont blame you for being cautious with overclocking on expensive new (rma) 5870.
Afterall, its not like you need to overclock to catchup.. its ALREADY the FASTEST.

Besides. 1000Mhz. 1100Mhz. Even 1300Mhz on GPU.. that's peanuts in terms of performance improvement compared to what driver optimizations bring (which also have the advantage of being cumulative and compounded!!).

Judging based on driver timelines of X1900, HD3870, and HD4870 - need HD5xx to wait 3-4 months for most major improvements (DX9/DX10) and probably till summer '10 to top out (especially since virtually no DX11 titles to optimize for right now).

Your HD5870 is only gonna get faster ;)