Microstuttering tests on ATI Radeon HD 4870 X2

[gosh]

So to understand what is causing delays in the GPU, you posted an untested and unproved theory on a CPU?

Proof would come from testing the hypothesis.

Fail.

Here is one test that could indicate that there is some problems in the total package for Intel when games are running on high res and/or is advanced in graphics.
In these tests one Phenom 9600 (2.3 GHz, 2MB L2 cache) wins over one C2Q (3,2 GHz, 12MB L2 cache)
http://www.overclockersclub.com/revi...l_q9450/14.htm
http://www.overclockersclub.com/revi...l_q9450/13.htm
http://www.overclockersclub.com/revi...el_q9450/8.htm
It seems that games that are heavy on I/O is a problem on Intel. If it is something wrong with the motherboard or other problems there I don’t know. But that is the only test I have found where they compare AMD with Intel on high res with PCI Express 2.0. Video Card used is 8800GT

[Hornet331]

Here is one test that could indicate that there is some problems in the total package for Intel when games are running on high res and/or is advanced in graphics.
In these tests one Phenom 9600 (2.3 GHz, 2MB L2 cache) wins over one C2Q (3,2 GHz, 12MB L2 cache)
http://www.overclockersclub.com/revi...l_q9450/14.htm
http://www.overclockersclub.com/revi...l_q9450/13.htm
http://www.overclockersclub.com/revi...el_q9450/8.htm
It seems that games that are heavy on I/O is a problem on Intel. If it is something wrong with the motherboard or other problems there I don’t know. But that is the only test I have found where they compare AMD with Intel on high res with PCI Express 2.0. Video Card used is 8800GT

lol again this strange review...

look at the cod4 test and compare the 1680x1050 with the 1920x1200 (ocend q9450). There is no chance in hell that with the same single (stock) 8800gt the framerate stays the same when you increase resolution, not even a gazillion more mhz on the cpu will make your game run faster, when the limintig factor is the gpu...

Same with WiC but now on the phenom rig -> 1027x768 28fps -> 1280x1024 28fps -> 1680x1050 28fps -> 1920x1200 28fps....

[gosh]

lol again this strange review...

is it?

The thing is that I believe this test is more creditable because it isn’t perfect. There is a lot going on in gaming and there could be other things on the computer that effects the game, of course it could be the human factor. But the thing is that the scores seems to be honest, they don’t care if it looks strange.

The big problem is that there is so very hard to find test that somehow is checking this problem. You need to compare one slow and one fast processor on high res with one very fast video card. The speed can’t be hindered by the processor speed or the video card. Best would be to compare one slow AMD Phenom ( 9550) with a good motherboard, now that these 790GX is coming that would be very interesting to compare, with one very high clocked Intel and a very fast Video Card. Then you have one solution that has very strong I/O but the processor isn’t that fast. Another solution that has very strong processor but I/O and memory transfers isn’t that fast. Checking the behavior on these computers would say a lot on why things happens.

There is another scenario that is similar to that if you compare one single core processor with a dual core. If you have one single core processor is running at 3 GHz and one dual core running at 1.5 GHz. You are using these for normal work as word processing, surfing, chatting e.t.c. What processor would get the most pleasant experience?
If you test these then the 3 GHz will win big over dual @ 1.5 GHz
If the 3 GHz runs some threads and one thread is set to higher priority and that thread does some demanding operations, then what happens to the other threads? They just stop.
If one thread crashes on then 3 GHz in a loop with higher priority, then the other threads also will be veeery slow.
What happens if a game is multithreaded or there are some other threads in the background of a game? That thread is set to high priority and does some memory intensive thing. Remember that the only path C2D and C2Q has to communicate with other hardware is the Front Side Bus. That traffic is probably controlled by hardware but it could be that two threads is located on the same core, other threads could also be waiting for one thread to get ready.

[Hornet331]

The big problem is that there is so very hard to find test that somehow is checking this problem. You need to compare one slow and one fast processor on high res with one very fast video card. The speed can’t be hindered by the processor speed or the video card. Best would be to compare one slow AMD Phenom ( 9550) with a good motherboard, now that these 790GX is coming that would be very interesting to compare, with one very high clocked Intel and a very fast Video Card. Then you have one solution that has very strong I/O but the processor isn’t that fast. Another solution that has very strong processor but I/O and memory transfers isn’t that fast. Checking the behavior on these computers would say a lot on why things happens.

and thats the problem with that review, they are using a 8800gt, and this should mean they should see serious drops in res above 1650x1050, yet there are some total inconsistent numbers (there are a lot more in that review, then the few i have pointed out.)

What happens if a game is multithreaded or there are some other threads in the background of a game? That thread is set to high priority and does some memory intensive thing. Remember that the only path C2D and C2Q has to communicate with other hardware is the Front Side Bus. That traffic is probably controlled by hardware but it could be that two threads is located on the same core, other threads could also be waiting for one thread to get ready.

most games arn't really memory bandwidth hungry. Thats why you only see a very low increases in fps (even on the amd platform) when you use faster ram.
I also play games and do some crunshing (rosetta) at the same time, but i never noticed any slowdowns while i play games, not on SC or crysis.

As said in aother thread, this review needs some deeper digging and some crosschecking.

[gosh]

most games arn't really memory bandwidth hungry.

No but some are very I/O hungry and the problem here is GRID. That game seems to scale well using threading and it is also intensive in graphics. And what we are discussing here is situations that could slow the game temporarily.
If the problem was in the GPU then it would be more logical that it showed up I more games. New games that will be out and if they are heavy on I/O, is using more threads will probably confirm or prove it false.

[Hornet331]

No but some are very I/O hungry and the problem here is GRID. That game seems to scale well using threading and it is also intensive in graphics. And what we are discussing here is situations that could slow the game temporarily.
If the problem was in the GPU then it would be more logical that it showed up I more games. New games that will be out and if they are heavy on I/O, is using more threads will probably confirm or prove it false.

any source for that claims?

i just played a bit with the system monitor in xp, which allowes you to log I/O for a certain app. Crysis has avg ~100 I/O per second and ~1,7mb/s transferred (peak of ~50mb/s and 6000 I/O while loading) (level was onslaught, which has quite some action going on. )

i dont know for grid, but i doubt it will be significantly higher.

[gosh]

any source for that claims?

i just played a bit with the system monitor in xp, which allowes you to log I/O for a certain app. Crysis has avg ~100 I/O per second and ~1,7mb/s transferred (peak of ~50mb/s and 6000 I/O while loading) (level was onslaught, which has quite some action going on. )

I don’t think that you only have ~100 I/O requests per second to the GPU playing Crysis You have A LOT MORE.
Also it isn’t the size that is important; it is the number of requests to memory and GPU that is important.
If you fetch 1000 bytes (not much) but you get one byte on each request. If you have a cache miss for each request and say that it takes about 250 clocks to get it. Then you have 1000 * 250 = 250 000 clocks getting 1000 bytes. Compare this with finding data in the L2 cache (15 clocks). 1000 * 15 = 15 000 clocks. If the Front Side Bus is working with another thread or cache is used for another application the hit rate will go down and as you can see in this example the speed is will go down.
If one thread has all these misses in the cache and slows down and there are another thread that is dependent on work to be ready then that thread will also be slower

Now it will not be that ineffective in games but normally it is small requests and it isn’t the size that matters, it is the latency for each request. OC the FSB will improve performance for the whole computer on Intel because latency goes down.

Crysis is almost one single threaded game and the problem with scaling may not show up there. If just one thread manages the I/O and/or it also will be the main memory user then I don’t think it will be a problem.
If you are using a lot of threads and all threads are sending or getting information than complex situations could appear. Not often but in a world that executes ~2 000 000 000 operations each second it could be often if we think about it. Also if there are other applications in the computer that is working the game will have to share resources and that slows it down.

On AMD the situation is different because it has Hypertransport and that manages I/O alone, it doesn’t need to compete with memory traffic. Also AMD Phenom can read and write data at the same time.

[JohnZS]

lol again this strange review...

I was thinking the same thing it seems that AMD CPU fanboys which are really dedicated to the cause (those who refuse to leaving in droves like pilgrims to the promised land of Core2) always rake that review out.

I think..

They have a point, it's nothing to do with the CPU, but more to do with the chipsets I belive the AMD chipsets have a faster or a more favourable PCI-E 2.0 controller, either that or Intel X38 and X48 boards require a BIOS update to ensure that there are no bottlenecks at higher resolutions


I vaguely remember reading something along the lines (slightly off topic) that Intel ICH only offers six PCI Express lanes, while AMD relies on its north bridges for PCIe links, but that might not be true.

Anyway I think ATi have done something to reduce microstutter (judging by the results in this thread), however it looks like it might still be around...only subjectively though...or very hard to detect.

John

[Hornet331]

I vaguely remember reading something along the lines (slightly off topic) that Intel ICH only offers six PCI Express lanes, while AMD relies on its north bridges for PCIe links, but that might not be true.

the northbridge of x38/x48 has 32 pcie 2.0 lanes and the ICH(R)9 southbridge offers another 4 lanes.

For P45 it is 16 pcie 2.0 lanes and 6 on the ICH10.

Anyway I think ATi have done something to reduce microstutter (judging by the results in this thread), however it looks like it might still be around...only subjectively though...or very hard to detect.

John

i think the main factor, why there is less stuttering is, that the cards are faster. Make fun of it, but i think thats the biggest reason why we dont see MS so offten now. MS is mostly noticed in the 30-40 fps regoin, in most games now CF can push past this limit -> less MS.

[villa1n]

Here is one test that could indicate that there is some problems in the total package for Intel when games are running on high res and/or is advanced in graphics.
In these tests one Phenom 9600 (2.3 GHz, 2MB L2 cache) wins over one C2Q (3,2 GHz, 12MB L2 cache)
http://www.overclockersclub.com/revi...l_q9450/14.htm
http://www.overclockersclub.com/revi...l_q9450/13.htm
http://www.overclockersclub.com/revi...el_q9450/8.htm
It seems that games that are heavy on I/O is a problem on Intel. If it is something wrong with the motherboard or other problems there I don’t know. But that is the only test I have found where they compare AMD with Intel on high res with PCI Express 2.0. Video Card used is 8800GT

LMAO, you mean there could be a shred of legitimacy to the "smoother" feel of an AMD system... It could be the case, i had never considered I/O lag :P