4850@750Mhz vs 4870

[keiths]

The question has been brought by people a few times about how much the performance of the 4870 is its memory bandwidth or GPU. The 4870 reviews give results for it, but haven't seen any results for a 4850 /w its GPU clocked to 750, so this is asking if some 4850 owners would bench something at 750 so that a rough comparison could be made.

[keninishna]

check the 700 MHz barrier smashed thread in the xtreme bios section. Someone scored over 30k in 3dmark 05 at 800 mhz on GPU the only problem is your gonna have to wait for some 4870 3dmark 05 benches.

[keiths]

Yes, it's already known that 4850s are clocking past 750. That's not the point. Again, I and others are interested in seeing the difference the 4870's memory bandwidth makes, doing so by clocking the 4850 core the same as the 4870. One can then better compare with the 4870 reviews. I say better, as the platforms will by chance be different.

[gundamit]

If you want to isolate the memory performance difference, wouldn't it be easier just to drop the core on the 4870 to 700 then measure against the a CCC Oc'ed 4850 at the same core clock?

[keiths]

No. The desire to is to be able to compare results from 4870 reviews and 750 is nothing to achieve; 4850 has been clocked to 900 already, with stock heatsink no less. That's sort of the issue, people have just been clocking to the max, not doing a comparison like this.

[aldamon]

I want to see this kind of comparison, too.

How starved for memory bandwidth is the 4850 at 800+ with max memory speed?

How does it compare to the 4870 overclocked to 800+ and max memory speed as well?

[oohms]

According to the expereview 4870 review, the 4870 is on average 25% faster.. but i agree, i would like to see just how memory limited these cards are

[gurusan]

Well my 4850 is only at 700/1100 at the moment because I'm waiting for some cooling things to come before I push it.

However, I did have it at 750/1100 briefly on 1.23v and did 2 crysis benches. First one is 1280x1024 all high, no AA. 2nd bench is 1680x1050 All very high, DX10, no AA....and the GPU was at 810mhz at the time as well :/ sorry but it's all i have. I don't really bother with 3dmark06 because 1) these 48xx series don't seem to do particularly well in 3dmark...and 2) because game benchmarks are what matter...screw synthetics :p

[aldamon]

According to the expereview 4870 review, the 4870 is on average 25% faster.. but i agree, i would like to see just how memory limited these cards are

Yeah, but that 25% difference was at stock speeds. 750 is 20% higher than 625, so are we to assume that at stock speeds, the GDDR5 only gives the 4870 a 5% advantage, clock per clock? That's a pretty crappy value if so and would explain the BIOS lock. I'm curious to see if that gap widens with higher core speeds.

[keiths]

Just as helpful would be for those with a 4870 to underclock their gpus to 625 and bench something to see what performance results from the memory bandwidth.

[keiths]

Alright, I've gone through the 4870 review thread list(http://www.xtremesystems.org/forums/...ht=4870+review,) grabbed all the comparable results, sorted, giving us the following:

crysis dx10 high noaa
gurusan e6750@3.6
1280x1024 33.78 48.52 58.68 4850@750
1680x1050 16.74 22.88 27.00 4850@810 very high

anand qx9770@3.2
1280x1024 ??.?? 45.50 ??.?? 4870
1680x1050 ??.?? 35.60 ??.?? 4870
1280x1024 ??.?? 37.40 ??.?? 4850
1680x1050 ??.?? 29.80 ??.?? 4850

pcper x6800@2.93
1280x1024 23.00 43.10 57.00 4870

hardwarecanucks qx9770@3.85
1280x1024 25.98 40.61 ??.?? 4870
1280x1024 23.11 34.27 ??.?? 4850

expreview qx9650@4.0
1680x1050 ??.?? 40.46 ??.?? 4870
1680x1050 ??.?? 32.58 ??.?? 4850

chw.net qx9650@3.0
1680x1050 20.90 38.00 ??.?? 4870
1680x1050 11.70 30.50 ??.?? 4850
very high
1680x1050 02.00 16.50 ??.?? 4870
1680x1050 02.90 13.10 ??.?? 4850

legitreviews qx9770@3.2
1280x1024 ??.?? 38.30 ??.?? 4870
1280x1024 ??.?? 34.80 ??.?? 4850

1280x1024 crysis dx10 high noaa
33.78 48.52 58.68 4850@750 gurusan e6750@3.6
??.?? 45.50 ??.?? 4870 anand qx9770@3.2
23.00 43.10 57.00 4870 pcper x6800@2.93
25.98 40.61 ??.?? 4870 hardwarecanucks qx9770@3.85
??.?? 38.30 ??.?? 4870 legitreviews qx9770@3.2
23.11 34.27 ??.?? 4850 hardwarecanucks qx9770@3.85
??.?? 37.40 ??.?? 4850 anand qx9770@3.2
??.?? 34.80 ??.?? 4850 legitreviews qx9770@3.2

1680x1050 crysis dx10 high noaa
??.?? 35.60 ??.?? 4870 anand qx9770@3.2
??.?? 40.46 ??.?? 4870 expreview qx9650@4.0
20.90 38.00 ??.?? 4870 chw.net qx9650@3.0
??.?? 29.80 ??.?? 4850 anand qx9770@3.2
??.?? 32.58 ??.?? 4850 expreview qx9650@4.0
11.70 30.50 ??.?? 4850 chw.net qx9650@3.0
22.20 36.70 ??.?? 260gtx chw.net qx9650@3.0

1680x1050 crysis dx10 very high noaa
16.74 22.88 27.00 4850@810 gurusan e6750@3.6
02.00 16.50 ??.?? 4870 chw.net qx9650@3.0
02.90 13.10 ??.?? 4850 chw.net qx9650@3.0
09.30 16.40 ??.?? 260gtx chw.net qx9650@3.0
??.?? 26.59 ??.?? 280gtx stelaras e8500@3.8 http://www.thelab.gr/showthread.php?t=52224&page=16
13.44 19.38 23.34 4870@625 dnottis q6600@3.6

Thanks to gurusan responding; could use some more data points and other game benches(hint, hint 4850/4870 owners)

Hunt turned up a forum post of a 280gtx for 1680x1050 very high. 4850@900 should about match this.

[aldamon]

keiths, gurusan's second set of Crysis numbers is at Very High, not High.

[keiths]

Ah, missed that. There was only one or two reviews that benched at very high, so it'd be helpful if gurusan benched at high, but I'll look at tracking those results down again.

[Truckchase!]

here's a different take on how to tell what impact mem bandwidth is having...

1> benchmark 4850 @ stock speeds
2> oc the GPU and vMem by a static percentage (15&#37 and bench
3> OC just the GPU and Just the vMem by the same static percentage and benchmark each oc seperately.

Compare the results to see how large of an impact the vMem overclocking has on performance vs. the gpu. In all actuality, you need only to do step 1 and 3, but 2 is always fun to compare against to make sure there isn't an odd unknown variable.

Here's an example from when I did this on a 2900xt:
http://www.xtremesystems.org/forums/...5&postcount=31

I'm willing to do this, as I have an unopened HIS 4850 sitting here, but last night I ordered a 4870, so I was just gonna return the '50. Anyone wanna buy a slightly used 4850 for $175 next week so I can do the 4850 benching this weekend?

edit: I'll do the testing on the new 4870 when I get it as well.... I've got an automated test suite that makes it pretty easy.

[keiths]

Lucked out. One review had 1680x1050 at very high noaa. Updated the listing.

[keiths]

My critique of what little results there are so far is the gpu is the significant factor and the memory difference not even registering, for crysis at least. Of course, this is just at 1280x1024 and 1680x1050. Need some higher res benches and aa.

[gurusan]

here's a random result that won't help you with any direct comparisons but figured I'd throw it in here:

[aldamon]

My critique of what little results there are so far is the gpu is the significant factor and the memory difference not even registering, for crysis at least. Of course, this is just at 1280x1024 and 1680x1050. Need some higher res benches.

I agree and if it doesn't register in Crysis, then where would it register? Nothing else touches Crysis.

[Truckchase!]

I agree and if it doesn't register in Crysis, then where would it register? Nothing else touches Crysis.

Crysis is all math. There isn't much strain put on the memory. Did you guys read my post? This is a pretty simple issue that one guy with a 4850 could solve....

[aldamon]

You shouldn't have to do that. It's a shame that the dozens of hardware sites, that had both cards in their possession, didn't run this kind of test so you wouldn't be put in that position. It's like they took for granted that the 4850 would never hit the core speed of the 4870 and just ignored the possibility the GDDR5 is all fluff.

[TheScavenger]

I am interested in seeing these comparisons as well.

[Hornet331]

hmm i think oblivion with texture pack would stress memory, thought it also would stress the core a lot.

[gurusan]

a simple 3dmark06 SM2 and SM3 run would work if I ran it at 1680x1050 8xAA 16xAF...no?

And how about UT3bench with 16xAF and 8xAA 1680x1050

[keiths]

Need to be able to compare, so need to choose from the games and settings the reviews use, unless you can find some results from forums with the same game and configuration like I happened to find with the 280gtx result to compare with your very high run.

Truckchase!, a mild overclock shows the difference between GPU and memory, but it's less likely to show where the performance drop off is at, the 4850@750 and 4870@625 allows to compare to any review, and satisfies that whatif itch of a question of medium vs high end card. Also of interest and in the same vain as the medium vs high end whatif is max overclock vs 260/280gtx competition/topdog.

[Truckchase!]

Need to be able to compare, so need to choose from the games and settings the reviews use, unless you can find some results from forums with the same game and configuration like I happened to find with the 280gtx result to compare with your very high run.

Truckchase!, a mild overclock shows the difference between GPU and memory, but it's less likely to show where the performance drop off is at, the 4850@750 and 4870@625 allows to compare to any review, and satisfies that whatif itch of a question of medium vs high end card. Also of interest and in the same vain as the medium vs high end whatif is max overclock vs 260/280gtx competition/topdog.

1. What performance drop off? GPU, memory, both? Be specific.
2. You can't compare to a review. They have different base hardware, different OS, different benching techniques, etc. On top of that I can't guarantee the skill of the tester. (nor should you)
3. Max overclock will vary on a card by card basis, but obviously will reach an average. (as I believe you're getting at) However, the point of this thread is not to compare to Nvidia products, but to compare a 4850 vs. A 4870.

My point is that the main difference between a 4850 and 70 is the memory bandwidth. (yes I realize the voltage circuity is better on a 70) Given this information, one can conduct tests to see if the 4850 is memory bandwidth limited and answer the majority 4850 vs. 4870 question, which is the premise of this thread. That being said, I think I'm going to unwrap my 4850 tomorrow and do some tests since I have the automated scripts to do so. The offer still stands if anyone wants to buy this card since I'm getting 70 from FXVideoCards on Wednesday.

Edit: Oh snap, I didn't see that it was you that opened the thread until now KeithS.... do you want to change the context? I can't provide Nvidia data.... I'll just say they're "for the most part, faster and more expensive"