CPU bottleneck?

[dorfma05]

Quick question which I think I know the answer to but I just wanted to make sure:

If I am playing a game and I keep my windows task manager on the second screen. If the CPU usage never goes above 50-60% on 4 cores (all about evenly) is it possible for my FPS to be "CPU limited"? I'm assuming no but I figured I'd ask. (Running an i7 920 & GTX 580 both at stock frequency.)

Thanks,
J

 

[RavenSEAL]

If your CPU usage never goes above 50-60%, that means you are NOT CPU limited.

 

[boxleitnerb]

If your CPU usage never goes above 50-60%, that means you are NOT CPU limited.

That's not necessarily true. If a game loads only 2 cores fully, Windows task manager will show a usage well below 100% but you can still be limited. Perfect example: Skyrim. Scales well with clock speed up to 5 GHz (and possibly beyond) on a 2600K in some places but uses only 2-3 threads.

I don't quite trust the task manager concerning CPU load. The best way to determine a CPU limit would be to lower clock speed (can be done quickly through power options for instance) and have a look at the fps and if they drop by the same percentage. Everything else is just conjecture.

 

[apoppin]

Quick question which I think I know the answer to but I just wanted to make sure:

If I am playing a game and I keep my windows task manager on the second screen. If the CPU usage never goes above 50-60% on 4 cores (all about evenly) is it possible for my FPS to be "CPU limited"? I'm assuming no but I figured I'd ask. (Running an i7 920 & GTX 580 both at stock frequency.)

Thanks,
J

If you are running your i7-920 at stock frequency with a GTX 580 you are limiting your framerate in some games. Why not overclock? 3.4GHz makes a real difference in some games with a GTX 580.

 

[toyota]

If your CPU usage never goes above 50-60%, that means you are NOT CPU limited.

as boxleitnerb said, that is not always accurate. an accurate and quick way to check is to just simply lower the resolution and then check framerate. if the framerate stays basically the same than the cpu is the limitation in that case. a lot of games are sloppily done though and there will be cpu limited spots in certain areas of those games no matter what. in GTA 4 there are areas that drop into the 30s and even if I lower my res to 800x600, it stays about the same. and that's with my 2500k at 4.2. lol, and some people say that game is not unoptimized.

 

[happy medium]

A stock i7 920 will limit a gtx580 in some games.

 

[BFG10K]

You’re unlikely to be CPU limited in most games unless you’re running low detail levels.

You also generally can’t infer CPU limitations from Task Manager.

 

[LiuKangBakinPie]

Why not do the simple test. My appoligies if someone mention it already but currently I'm on the mobile and can't check all the posts like the pc. But anyways

Simple method
Put all the settings up related to the gpu and graphics in the game. Note your fps.

Then drop all the settings to low i.e like disabling AA etc etc.
Then note your fps. If they're around the same number then your cpu is the bottleneck.
If they fluctuate quite a bit then your gpu is the bottleneck

 

[toyota]

why do people make this so hard? all you have to do is lower the res and check the framerate like I mentioned earlier. if its the same framerate at the lower res than your cpu is a limiting factor in that case. it takes less than 30 seconds to solve this mystery.

 

[happy medium]

why do people make this so hard? all you have to do is lower the res and check the framerate like I mentioned earlier. if its the same framerate at the lower res than your cpu is a limiting factor in that case. it takes less than 30 seconds to solve this mystery.

because they are not as smart as the all mighty Toyota? :thumbsup:

 

[LiuKangBakinPie]

why do people make this so hard? all you have to do is lower the res and check the framerate like I mentioned earlier. if its the same framerate at the lower res than your cpu is a limiting factor in that case. it takes less than 30 seconds to solve this mystery.

oh yeah lol that's even a faster method.
But some people will rather go through hell and back before they drop a resolution on a LCD. Dunno why maybe they heard stories of the boogie coming if they do that

 

[dorfma05]

Well, after running at stock speed since launch, I finally decided to overclock it. I just overclocked it to 3.8 GHz, can't believe how easy it was.

Anyway, it yielded absolutely no change in FPS so I must be GPU limited.

I'm getting about 25-30 FPS in Skyrim with a GTX 580. I may have gone a little nuts with the shaders, I heavily modified the INI file.

I guess I'll either scale back or just grab two GTX 600's when they come out.

 

[LiuKangBakinPie]

What resolution are you on 1080p?

 

[toyota]

Well, after running at stock speed since launch, I finally decided to overclock it. I just overclocked it to 3.8 GHz, can't believe how easy it was.

Anyway, it yielded absolutely no change in FPS so I must be GPU limited.

I'm getting about 25-30 FPS in Skyrim with a GTX 580. I may have gone a little nuts with the shaders, I heavily modified the INI file.

I guess I'll either scale back or just grab two GTX 600's when they come out.

25-30 fps with a gtx580 and i7 at 3.8? that does not sound right at all.

 

[happy medium]

I'm getting about 25-30 FPS in Skyrim with a GTX 580

WHat? no freakin way, something is wrong with your system.

A i7 @ 3.8 with a gtx 580 should max Skyrim easily.

Even @ 2500x1600 it should be just fine.

 

[LiuKangBakinPie]

You sure its not v-sync dropping your frame rates?
Does Skyrim support tripple buffering?

 

[BFG10K]

We still don’t even know what resolution or AA settings he’s using. For all we know he could be running super-sampling or vsync, in which case a CPU overclock will do squat.

 

[happy medium]

We still don’t even know what resolution or AA settings he’s using. For all we know he could be running super-sampling or vsync, in which case a CPU overclock will do squat.

25 to 30fps with a gtx580 and a i7 @ 3.8?
I don't care if hes running 2500x1600, thats still way too slow.

 

[LiuKangBakinPie]

Check the 460 doing better than the 570

Eek that's Sli sorry. On 1080p your performance should be just above the 570. 6 to 10 fps above it depends. Wonder why they didn't test the 580. They tested the 6970

 

[toyota]

http://media.bestofmicro.com/7/S/315208/original/TrAA%201920.png
Check the 460 doing better than the 570

that's SLI. the gtx570 is beating the crap out of a single gtx460.

 

[BFG10K]

25 to 30fps with a gtx580 and a i7 @ 3.8?
I don't care if hes running 2500x1600, thats still way too slow.

Are you familiar with super-sampling or vsync?

 

[dorfma05]

This is my first time with a "nice" video card since I had a 9800pro (just to give an idea).

I am running way above ultra settings with a heavily tweaked INI file. I may have gone a bit overboard tho.

I'm running at 1080 with 16x AF.

I'm running it with vsync and 8x supersampling if that is what you were asking.

I just dropped it to 2x supersampling and it only went up to 30-35 FPS.

Are there any major performance killers I should check/change?

 

[toyota]

sounds like you may have tweaked too much. hopefully you have a back up of original files because you need to go back to that IMO. and try it with vsync off though just to see if that helps.

 

[happy medium]

Are you familiar with super-sampling or vsync?

Ok you were right. The guy is image quality crazy.

 

[dorfma05]

sounds like you may have tweaked too much. hopefully you have a back up of original files because you need to go back to that IMO. and try it with vsync off though just to see if that helps.

I switched back and I'm barely seeing any change. I also tweaked a few things in the NVIDIA inspector program, like forced 8x supersampling, vsync, 16x AF...

Something doesn't seem right... I have the latest drivers...