If GPU never reaches 100% load but there are still framerate drops

[PieIsAwesome]

I decided to use rivatuner to monitor framerate, frequencies, and GPU usage under Unreal Tournament 3.

I have the framerate locked at 60 fps with vsync, and when I get framerate drops GPU usage is still low. For example, when the framerate drops to the 40s the gpu usage was in the 50s, under 60%. GPU usage never actually goes to 100%, but of course this is because of vsync.

Frequencies were normal, 750/2000.

Specs: e5200@ 3.0 ghz, 4GB DDR2-800, 4670@stock.
UT3 at max with vsync and 1280x720 (using TV).

This isn't a problem I am looking to fix or anything, just curiosity.

 

[SickBeast]

You may be CPU limited at such a low resolution.

UT3 is a very CPU intensive game, and I'm pretty sure it actually likes a quad core.

Your assumption may well be valid some of the time, but I would not take it as the gospel. There can be other factors at play.

I know that in Crysis the game can only show a 25% CPU usage, but it is still CPU limited in a sense.

You can actually be platform limited in games. :Q

 

[n7]

Almost for certain you are somewhat CPU-bound with your CPU in UT3.

It very much loves cores & cache.

I could never get the game truely playable (smooth fps without huge dips) with my Opteron 165, & my E1200 @ 3 GHz wasn't much better if at all (never did detailed testing).

You can solve this by getting a quad (it'll use all the cores quite nicely), or a higher clocked dual, or at least one with more L2.

My E6600 was fine, & same with my Q6700 with only two cores running, but it gets better minimum fps with all four cores going, at least in my testing.

 

[badnewcastle]

Change your resolutions... if you see little change in performance at different resolutions, then you are CPU is the bottleneck... otherwise you have a bottleneck somewhere else.

 

[dug777]

While I doubt it's the case here, if you are very memory bandwidth limited you can also see a low GPU load (my 4850 at 800/1028 often rolls along at below full GPU utilisation when my Q6600 is also comfortably below full utilisation).

EDIT:

Looking at this it would seem unlikely that your CPU at 3GHz is the culprit, unless it's changed dramatically since beta (and I don't see why it would have changed for the worse, anywho!).

http://www.anandtech.com/video/showdoc.aspx?i=3127&p=7