GTA IV: Where's the bottleneck?

[dug777]

Graphics card memory limitations?

In the examples below, when I say maxed, its as high as I could turn it up with my machine (and I assume my 4850 (512mb) limits this).

Machine is a Q6600@stock, 4850@775/1006(I think), 4GB DDR2, in a P5Q PRO.

Resolution is 1600x1200. CPU & GPU loadlines are taken from completely random fast burns in a 'vette around the city, usually ending in an epic fender-bender

First up: auto configure for numbers and text options (higher, highest etc) maxed:

http://pics.bbzzdd.com/users/d...ndmaxedtextoptions.jpg

We then look at everything maxed:

http://pics.bbzzdd.com/users/dug777/Allmaxed.jpg

Both CPU (average) & GPU core loading has dropped, but my FPS definitely suffered...

Core 1 is interesting, its loading has increased. Maybe the multi-threading isn't/can't break certain discrete tasks down across all cores?

It could be able to spread discrete tasks over the four cores, but that won't save you if one task/group of tasks allocated to one core is more than that core can handle (which would explain FPS drop (you are limited by that core), and a lower loading on other cores (other tasks are being 'held back' by that one)...

Or I could be missing something very obvious...

 

[vj8usa]

I made a similar thread a little while ago and people just told me I was CPU limited, even though I was seeing my framerate drop significantly just when I was increasing graphics options (I'd turn up resolution or shadows and see my framerate suffer, while GPU usage was consistently around 50%). I have no idea what to believe anymore when it comes to this game's performance.

 

[Phew]

OR it could just be that the game is a really bad console port, and it just doesn't use PC resources efficiently.

 

[error8]

Originally posted by: Phew
OR it could just be that the game is a really bad console port, and it just doesn't use PC resources efficiently.

This is what I'm also thinking.

 

[MrK6]

Originally posted by: Phew
OR it could just be that the game is a really bad console port, and it just doesn't use PC resources efficiently.

+2

Crap coding will tank your FPS, no matter how much power you have.

 

[toyota]

it really should be no secret by now that 512mb is not enough for that game if you want to crank the settings.

 

[chizow]

Originally posted by: dug777
It could be able to spread discrete tasks over the four cores, but that won't save you if one task/group of tasks allocated to one core is more than that core can handle (which would explain FPS drop (you are limited by that core), and a lower loading on other cores (other tasks are being 'held back' by that one)...

That seems most in-line with what I've seen in both GTA4 and other titles that do allow for different synchronization settings for frames, physics, and Vsync (like Fallout 3, ETQW, UE3.0 etc).

Most of the visual quality settings in GTA4 are still tied to CPU performance, so on a higher end GPU the additional strain on the CPU will only serve to further limit the potential performance of your GPU. As you guessed, CPU limitations are further reducing the number of frames generated for the GPU to render.

If you don't mind overclocking, you can test this quite easily yourself. At identical settings, increasing CPU clock should result in higher FPS and higher % GPU utilization. Also, running the in-game benchmark might give you more accurate quantifiable results, even if they aren't as accurate a reflection of real gameplay.

Originally posted by: MrK6

Originally posted by: Phew
OR it could just be that the game is a really bad console port, and it just doesn't use PC resources efficiently.

+2

Crap coding will tank your FPS, no matter how much power you have.

You guys aren't having problems with GTA4 are you? Both of your rigs with Quads should be chewing through the game and providing an excellent gaming experience.

 

[MrK6]

Originally posted by: chizow

Originally posted by: dug777
It could be able to spread discrete tasks over the four cores, but that won't save you if one task/group of tasks allocated to one core is more than that core can handle (which would explain FPS drop (you are limited by that core), and a lower loading on other cores (other tasks are being 'held back' by that one)...

That seems most in-line with what I've seen in both GTA4 and other titles that do allow for different synchronization settings for frames, physics, and Vsync (like Fallout 3, ETQW, UE3.0 etc).

Most of the visual quality settings in GTA4 are still tied to CPU performance, so on a higher end GPU the additional strain on the CPU will only serve to further limit the potential performance of your GPU. As you guessed, CPU limitations are further reducing the number of frames generated for the GPU to render.

If you don't mind overclocking, you can test this quite easily yourself. At identical settings, increasing CPU clock should result in higher FPS and higher % GPU utilization. Also, running the in-game benchmark might give you more accurate quantifiable results, even if they aren't as accurate a reflection of real gameplay.

Originally posted by: MrK6

Originally posted by: Phew
OR it could just be that the game is a really bad console port, and it just doesn't use PC resources efficiently.

+2

Crap coding will tank your FPS, no matter how much power you have.

You guys aren't having problems with GTA4 are you? Both of your rigs with Quads should be chewing through the game and providing an excellent gaming experience.

Great points. Believe it or not, performance on my rig is less than stellar . I'm waiting until I upgrade to i7 in a month or two to play through the whole game so I can really enjoy it in all its glory (i.e. all options cranked).

 

[dflynchimp]

Originally posted by: chizow

Originally posted by: dug777
It could be able to spread discrete tasks over the four cores, but that won't save you if one task/group of tasks allocated to one core is more than that core can handle (which would explain FPS drop (you are limited by that core), and a lower loading on other cores (other tasks are being 'held back' by that one)...

That seems most in-line with what I've seen in both GTA4 and other titles that do allow for different synchronization settings for frames, physics, and Vsync (like Fallout 3, ETQW, UE3.0 etc).

Most of the visual quality settings in GTA4 are still tied to CPU performance, so on a higher end GPU the additional strain on the CPU will only serve to further limit the potential performance of your GPU. As you guessed, CPU limitations are further reducing the number of frames generated for the GPU to render.

If you don't mind overclocking, you can test this quite easily yourself. At identical settings, increasing CPU clock should result in higher FPS and higher % GPU utilization. Also, running the in-game benchmark might give you more accurate quantifiable results, even if they aren't as accurate a reflection of real gameplay.

Originally posted by: MrK6

Originally posted by: Phew
OR it could just be that the game is a really bad console port, and it just doesn't use PC resources efficiently.

+2

Crap coding will tank your FPS, no matter how much power you have.

You guys aren't having problems with GTA4 are you? Both of your rigs with Quads should be chewing through the game and providing an excellent gaming experience.

As much as I'd like to believe it, as of status quo quad core utilization in games has still been all but minimal. GTAIV may or may not have been optimized to use more than one thread since 360 runs on a tri-core cpu, but the fact of the matter is if it's a console port to the PC, coding probably has not been optimized.

I don't have GTAIV on the PC, but if I were either of you I'd fiddle with the individual settings to figure out which ones tax the cpu more and which ones rely on the gpu the most, and just turn down the ones that are cpu limited.

 

[chizow]

Originally posted by: MrK6
Great points. Believe it or not, performance on my rig is less than stellar . I'm waiting until I upgrade to i7 in a month or two to play through the whole game so I can really enjoy it in all its glory (i.e. all options cranked).

I don't blame you for wanting to wait, while playing on the Q6600 @3.6 was great, playing on the i7 is on a different level. Benches do show the difference in FPS, but its still not fully accurate imo. i7's performance improvements per clock and HT certainly help, but I don't think that explains all of the perceived improvements. Part of it may be due to the shared L3 cache vs. split L2 on non-native Quads (Core 2) resulting in a smoother experience (Anand talked about this in his Phenom article). Part of it may also be due to the IMC and much higher bandwidth and timings available on i7, something I noticed when tweaking memory timings on my P45 (performance tanked when I relaxed tRFC).

 

[Cheesetogo]

What setting do you have view distance set at? It makes almost no visible difference (max view distance remains the same, it just slightly reduces the quality of distant objects when turned down) but it seems to make a pretty big performance hit. I'd suggest putting it around 30.

I would also STRONGLY suggest disabling the ingame video recording - the option is on by default and seems to be terrible for frame rates. Also, look around for the command line option to disable VSync - I think I gained 10-15 fps from doing that.

 

[Acanthus]

Originally posted by: Cheesetogo
What setting do you have view distance set at? It makes almost no visible difference (max view distance remains the same, it just slightly reduces the quality of distant objects when turned down) but it seems to make a pretty big performance hit. I'd suggest putting it around 30.

I would also STRONGLY suggest disabling the ingame video recording - the option is on by default and seems to be terrible for frame rates. Also, look around for the command line option to disable VSync - I think I gained 10-15 fps from doing that.

You can disable vsync in the normal graphics options menu.

GTA4 makes me want a 4870 2GB.

 

[solofly]

Originally posted by: MrK6
Great points. Believe it or not, performance on my rig is less than stellar . I'm waiting until I upgrade to i7 in a month or two to play through the whole game so I can really enjoy it in all its glory (i.e. all options cranked).

Unless you got 2gb on your video card (which you don't) all options wont be cranked.

 

[evolucion8]

GTAIV resources usage is buggy, is like if it had some kind of bottleneck somewhere. Mass Effect is a nice example of how a game can tax a Quad Core, it uses between 45% to 60% in each core, but the game doesn't look that great compared to others to be using that much CPU power, so that's because the current consoles rely quite much on CPU power to improve graphics a bit and when they're badly ported to PC, nothing is enhanced, so the same thing happens in PC, low GPU usage and high CPU usage.