100% GPU load in game

[Pottuvoi]

Everything can be rendered using the CPU. So, saying that it's a graphic setting, therefore it has to be GPU limited isn't always true. Since a lot of the calculations are highly parallel, the GPU is the best device to use, but they can have the CPU do it.

If they would use CPU framerate would be at single digits. (or SPF)

There would be 2 ways to do it.
1.
Render scene on GPU and send Z-Buffer back to main memory using PCI-E.
Render shadows on CPU by resolving world location from z-buffer data and using whatever method you want.
Send shadow mask back to GPU and use it with light calculations.

2.
Render identical Z-Buffer with CPU and use it to render shadow mask.
Send shadow mask back to GPU and use it with light calculations.

No, no-one in their sane mind use CPU to render random full resolution effects on CPU on PC.

 

[3DVagabond]

If they would use CPU framerate would be at single digits. (or SPF)

There would be 2 ways to do it.
1.
Render scene on GPU and send Z-Buffer back to main memory using PCI-E.
Render shadows on CPU by resolving world location from z-buffer data and using whatever method you want.
Send shadow mask back to GPU and use it with light calculations.

2.
Render identical Z-Buffer with CPU and use it to render shadow mask.
Send shadow mask back to GPU and use it with light calculations.

No, no-one in their sane mind use CPU to render random full resolution effects on CPU on PC.

I didn't say that they do that. I'm just saying that anything that can be rendered with the gpu could also be rendered with the cpu. Yes, it would be slower than hell. It's the way most renderers work in modeling/animation apps and it can take hours for one frame on a single CPU.

All I meant was that you can't be certain that a particular render setting isn't using the cpu for anything.

 

[PrincessFrosty]

Everything can be rendered using the CPU. So, saying that it's a graphic setting, therefore it has to be GPU limited isn't always true. Since a lot of the calculations are highly parallel, the GPU is the best device to use, but they can have the CPU do it.

I'm not making an argument over what is possible, but what actually happens, the CPU isn't drawing shadows, that would be insane.

If they would use CPU framerate would be at single digits. (or SPF)

No, no-one in their sane mind use CPU to render random full resolution effects on CPU on PC.

Exactly.

EVERY setting that keeps me from staying at 60 fps in GTA 4 on max settings with a gtx670 is cpu related NOT gpu related. I have probably spent more time testing this game then most people have playing it. shadows and view distance are a big problem for the cpu NOT just the the gpu and that is a fact. I already told you that I can lower the res in those cpu dependent spots and my framerates remain the same yet I can lower shadows and they go way up. that alone would tell that it is a cpu intensive setting.

EDIT: just tested it again at a very cpu intensive spot. at 1920x1080 with shadows on very high, I am at 26-27 fps and if I lower the res to 1280x720 then I am still at 26-27 fps in that same spot. heck I even lowered the res to 800x600 and I was still at 27 fps. shadows on very high kill my cpu NOT my gpu.

First of all draw distance will effect the CPU, I acknowledged that above, you're drawing more peds and traffic and the physics and AI governing these things require more CPU time.

All you've said is that shadows kill your frame rate, have you actually benchmarked this and measured load on your CPU and GPU during these times to actually show the CPU is maxing out?

 

[toyota]

I'm not making an argument over what is possible, but what actually happens, the CPU isn't drawing shadows, that would be insane.



Exactly.



First of all draw distance will effect the CPU, I acknowledged that above, you're drawing more peds and traffic and the physics and AI governing these things require more CPU time.

All you've said is that shadows kill your frame rate, have you actually benchmarked this and measured load on your CPU and GPU during these times to actually show the CPU is maxing out?

a cpu does not have to be maxed out at all to be the limitation. again all you have to do is lower the resolution and if the framerate stays the same then the game is limited by the cpu. lowering my res in GTA 4 from 1920x1080 to 800x600 and keeping almost the same identical framerate is clearly showing the cpu as the main limitation in those parts.

although not common as with the cpu, I have seen where a gpu can be the limitation too without actually being maxed out. this happens in LA Noire where my gpu could only maintain 25 fps even though the gpu was only at around 60% usage. lowering the res to 1280x720 made the framerate go right to 30 at the exact same spot and stay there even though gpu usage did not really change.