Cyclic GPU utilization problem

Dictator93

Hey everyone,
Don't usually post problems at all because my machine is fine. BUt I believe I have found some sort of bug in the game resulting in poor performance for basically no reason.

Before this most recent update my performance has been great. Infact, this update Improved my performance and made my GPU's (that is right SLI works in this game) work at all most 100% the whole time. Even with ambient occlusion on. I still get about 60 FPS.

But!

For some reason the game for no reason messes up every once and a while and drops my GPU utilization by almost a half. Then my game runs at about 30 or 35 fps. This happens, even though all I have done is move in a circle back to my original position. The only way to get my FPS up again, is to alt-tab. Then it is back at 60 fps with full gpu utilization.

The funny thing is, I was having this problem but my comp crashed while alt-tabbing the game. Restarted the game after reboot and the problem disappeared (full GPU utilization 60fps). It disappeared and everything was alright, but after I installed some new drivers the game ran poorly again. So I uninstalled them and went back to the old ones, but alas! the problem had returned! This time I just cannot shake it. I very much so regret installing those new drivers now...

here are some screen shots of the problem in action. Check out the FPS even though I am in the exact same location. All I did was move in a circle facing the same direction back to my original spot.

60 fps
<img src="http://www.abload.de/img/60fps6lqp9.png" border="0" class="linked-image" />

30 fps
<img src="http://www.abload.de/img/30fpso9qba.png" border="0" class="linked-image" />

The GPU utilization change showing what is causing the fps drop.
<img src="http://www.abload.de/img/theproblemwaogn.png" border="0" class="linked-image" />

Any clues? I'll be trying out a number of "solutions" in the mean time.

Update #1: Alt-tabbing the game fixes the GPU utilization and I am back to 60 fps. But then it returns again after moving around for a bit

Kouji_San

Could you post a screenshot of that 60FPS vs 30FPS with the profiler on, the profiler itself also eats up some FPS don't worry about that :)

type profile in the console and open up the high latency areas, you can type profile again to disable it.

Dictator93

Ok I used the profiler on veil in the areas where the GPU utilization trouble occurs. Then in a particularly rough spot I alt-tabbed the game to bring my fps back up so the difference would be apparent.

Edit2: Here are the pics

~30 fps header
<img src="http://www.abload.de/img/30fpsheader50ayt.jpg" border="0" class="linked-image" />

alt-tab ~60 fps header
<img src="http://www.abload.de/img/60fpsheader3wa3g.jpg" border="0" class="linked-image" />

That is me standing in the exact same location.
You can see how rendering is taking up 44% of load instead of just 4% when there is proper GPU utilization. I have a hunch it has to do with loading new vis-areas or something.
Also, as you can see at the last part of the GPU utilization graph. The game plateues at different GPU uttilizations depending upon the whether I had alt-tabbed or not.
<img src="http://www.abload.de/img/problem22i1jz4.png" border="0" class="linked-image" />

Dictator93

OK. Now please dont mind these large pictures. They are conglomeration pictures of the full profile for each frame (one for 30 fps and the other for 60)

Profile Conglomeration of Values for ~30 fps and ~60 fps at the same spot. Only Alt-tab difference
<img src="http://www.abload.de/img/bestcongolomoailub.jpg" border="0" class="linked-image" />

I am going to comb these images to try and find the difference.

Dictator93

Analysis:

I have noticed that it occurs most often whilst going around corners and turning. It appears when new Vis-areas load.
As you can tell by the Renderer taking more percentage of load time and the GC taking more load time.

At this exact same second the GPU utilization cuts in half for some reason. Then the FPS goes down. Alt-tabbing out and back into the game increases GPU utilization even though the same amount of geometry is being rendered (as far as I can tell).

If I could somehow maintain the same GPU utilization this problem would not be occurring. Something about loading the new Vis-area cuts GPU utilization, but then after loaded and after alt-tabbing to regain GPU utilization, the same loaded geometry and collision data is running fine.

Unsure as to the culprit which cuts the GPU utilization. Perhaps the way the data is sent to an SLI rig. It is not parsing it correctly or not sending it completely to either GPU. I know you guys have SLI rigs at the office (Hugh for example). If someone could corroborate and cooperate with me on this issue I would be quite grateful. Need more SLI users to chime in!

Dictator93

Ok I have been testing out some solutions to the problem.

Using Nvidia Inspector I have used game profiles and switched the .exe's from which they recognize the game, and then, use the SLI respective profile for NS2. I have found that some profile's reduce the stuttering (GTA4 profile and very much so the BFBC2 profile), and others get rid of it all together (Crysis 1 & 2, Planetside 2). The only problem with the Crysis and Planetside 2 profiles is that they cause shadow flickering. But other than that they actually enhance the games performance in SLI and give almost full GPU utilization. Frames always above 60 basically never going below. It is quite impressive. I will try more profiles out and eventually make a post on the Nvidia forums asking for SLI support for NS2 using existing profiles with tweaks. This should be of good benefit to all SLI users.

The method by which I accomplished this task was thinking about similarity between engines (dx9 deferred lighting with fully dynamic shadows) and then going from there to try out profiles.


Edit update: The best profile I have found so far is the one for Far Cry 3. It yields nearly constant 60fps with only a few minor dips (entering Stability monitoring only doe snot dip using the Crysis profiles)

Edit Update 2: The profile for Borderlands 2 locked when frame limited to 60fps is almost flawless. I recommend this one currently

Edit Update 3: The dishonoured profile is also quite good. It is rarely problematic and when Vsyncd, tripple bufffered, and thread optimized. It seems almost perfect expcept for the same problem areas (walking into stability monitoring is always a problem for some reason).

OmNomNom!

To test this, do I just find the borderlands 2 profile in nvidia inspector (for example) and click 'add application to current profile' and find the NS2.exe ? Is there any way to confirm the profile has in fact been applied?

Dictator93

Yep. That is how you do. Could you tell me if you incur the same problems that I do? Such as when walking into stability monitoring or going down the hallway from west skylights and looking left into the hallway that goes to stability motoring

Fratous

hey, just an update. I tried the room you mentioned and i don't have the utilization issue you are getting. Have you tried not selecting a profile and just forcing AFR 2 like i have?