How do I tell if a slowdown is caused by CPU, GPU, or VRAM?

Post » Tue Mar 08, 2011 1:34 pm

I've recently installed Better Cities, and the results in Cheyendhal combined with QTP3R is amazing. It's so gorgeous that I am loathe to uninstall any of it -- despite the fact that when I walk through Cheyendhal it stutters like mad!

So, I'd rather take the "fix the computer, not the game" approach to fixing this problem. Unfortunately, I'm not quite sure what is the most likely cause of the slowdown. It mostly occurs when I look down on a long stretch (Cheyendhal is a big cell, so I don't think the normal wilderness view distances apply) -- but I'm not sure what to make of that. It could be the CPU is trying to handle keeping track of / script-running on too many objects, or it could be that the GPU can't keep up or I don't have enough VRAM to satisfy the GPU (only 512 MB after all). Is there any way, any tool, to properly diagnose the issue?
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Javier Borjas
 
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Post » Tue Mar 08, 2011 3:09 pm

Type "TDT" in the console. Use the scroll lock button to cycle through the information until you get to a feedback text that shows the amount of VRAM being used. If it is using all your VRAM, then there will be stuttering as the card cycles data through the RAM. Your GPU is the main limiting factor for BBC, as it adds lots of new information to render.
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Marguerite Dabrin
 
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Post » Wed Mar 09, 2011 12:22 am

That's incredible, I had no idea I could use Scroll Lock to toggle through all that information. I'm assuming "texture memory" is referring to desired VRAM and, if so...sigh. Looks like fixing this is the more expensive upgrade, not the cheap $20 upgrade.

Thanks for the help! No idea I could access that kind of information from in-game.
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Eilidh Brian
 
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Post » Tue Mar 08, 2011 9:59 pm

What do your system specs look like?
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Cameron Garrod
 
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Post » Tue Mar 08, 2011 1:36 pm

Not terribly interesting. Intel E8400 (probably the best processor they ever made), Radeon HD4850 (the earlier 512 MB version), 4 GB of DDR2 RAM.

I double checked and the texture memory usage was actually remaining pretty constant, but the amount of geometry to render was spiking up past 3000 or so (I'm not sure what the unit is, I doubt it's "triangles") when my FPS started to svck. Maybe that cheap $20 upgrade can help after all.
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~Amy~
 
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Post » Tue Mar 08, 2011 1:22 pm

What cheap $20 upgrade would that be?
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krystal sowten
 
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Post » Wed Mar 09, 2011 3:03 am

Got a real soundcard? What operating system?
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Katie Louise Ingram
 
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Post » Tue Mar 08, 2011 6:42 pm

What cheap $20 upgrade would that be?

Sometime over the holidays, there was a Radeon HD4850 sale (old-style of the card I think) for $20. Video card sales have a tendency to repeat; I can just pop it in my computer in Crossfire with the current one and get some additional rendering power.

Got a real soundcard? What operating system?

Respectively: no, Windows 7. It's definitely the lack of rendering power that's slowing me down; though I'm close to hitting my VRAM ceiling too.
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Mashystar
 
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Post » Wed Mar 09, 2011 3:21 am

Adding an additional vid card isn't going to help you. I suspect your CPU is the bottleneck. For a quick and easy performance boost, disable music in the oblivion.ini located in my games\oblivion. Find the setting:

bmusicenabled=1

change the one to a zero, save and exit. Try the game again.
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Samantha Wood
 
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Post » Tue Mar 08, 2011 5:06 pm

That did absolutely nothing. Given that I only have framerate issues when the number of triangles shoots up dramatically. I strongly suspect it's a lack rendering power.
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Chris Johnston
 
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Post » Wed Mar 09, 2011 3:00 am

Just out of idle curiosity, what driver version are you using for your vid card?
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Gavin boyce
 
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Post » Tue Mar 08, 2011 9:07 pm

I'm using Catalyst 10.11.
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neen
 
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Post » Tue Mar 08, 2011 9:50 pm

See if rolling your drivers back to 10.4, or 10.6 gives any improvement. I seem to recall reading that the newer drivers were somewhat borked......
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kiss my weasel
 
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Post » Wed Mar 09, 2011 2:34 am

It's quite a bit of work, but pyffing your vanilla and qtp3 meshes may help by cutting down on the overall number of triangles that need to be rendered. (I think Better Cities is already Pyffied). Also, better cities includes optional FPS patches, make sure you have installed them.
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Sarah Bishop
 
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Post » Wed Mar 09, 2011 12:21 am

Yes. PyFFI'ing your meshes helps tremendously. But you must expect low FPS in cities when running Better Cities. I have 2 GTX 480's in SLI and get 10 - 12 (or so -- a little more, a little less) FPS in cities.
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Penny Wills
 
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Post » Wed Mar 09, 2011 5:17 am

You could always try Oblivion.ini tweaks as an alternate approach (though be careful--always make a backup copy first!)
Lowering the uGridDistant settings - which lowers the number of trees drawn in the distance - improved the stuttering in my game tremendously. But my computer is much less powerful than yours; you may see little difference.
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Britta Gronkowski
 
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