Strange Left 4 Dead PC problem

[sj33]

I've been playing the game for about a day now, and I get between 35 and 75fps throughout most of the game. However, after playing for about 10 minutes or so, it will suddenly drop right down to sub-5fps. I can continue playing and the framerate will return to normal, or I can pause it, grab a coffee and wait (not ideal if you're playing online)
Does anyone know what is causing this?

My first guess was that either the CPU or GPU is throttling because of high temperatures, but this does not seem to be the case. I've disabled CPU throttling with RMClock, and it is running at the full 2.49GHz. As for the GPU, the temperature isn't any higher than normal, and I've played more demanding games without this problem. I can only think that it is something with the game itself.

Any ideas?

Spec-
Dell m1330 13" laptop
Core2 Duo T9300 @ 2.49GHz
4GB DDR2 667MHz
GeForce 8400m GS 128MB DDR3
Windows 7 Release Candidate 64-bit
Dox modded Forceware 185.85 (have tried the official 186.03)

[Hohum]

Try setting the paged pool memory setting in the options to a lower level (and perhaps lower some graphics settings too, seeing as you have limited video RAM). If it still occurs, see if alt-tabbing to desktop and then going back to the game fixes it (which will indicate a lack of available memory if it does resolve it).

[sj33]

I did try the paged pool memory thing, as well as disabling multicore processing, it didn't seem to make any difference. Alt-tabbing does nothing, but it's strange that it seems to sort itself out if I just continue playing (or just pause). It's really bizzare, and I really think it's something to do with the game rather than my setup

On an unrelated note, I hate how they've removed the max_fps console command =/

[Hohum]

Not sure then, never had any problems myself. Presumably you have tried low settings across the board to rule that out (including turning off V-Sync and triple buffering in particular), so I don't know what else to suggest.

http://www.giantbomb.com/left-4-dead/61-20690/anyone-getting-slow-down/35-222597/

That guy had the same issue by the looks of it, although the way he resolved it probably won't be of much help to you.

[sj33]

It's bizzare that heat issues should only affect L4D though, especially given it occurs regardless of what graphical settings I use. I'll have to fiddle with it later. The game runs fine 95% of the time.

Also, do you know if there's another way to limit the fps now that they've removed the max_fps command (aside from using Vsync)? I generally like to cap Source/Goldsr games at 60, as this removes tearing without having to enable Vsync, as well as bringing temps down because it's rendering less frames. I thought I'd experiement with a 30fps cap on here, just to see what it's like.

[AlonzoUK]

Have you tried running it has a window:

"C:\Program Files\Valve\Steam\steam.exe" -applaunch 500 -noborder -windowed

Still runs full screen.

I had a similiar issue on my PC and this cleared it.

[Hohum]

That may work, although will entail a few other issues - gamma, V-Sync forced on or off (dependant on whether you use Aero or not), and you'll lose some performance (3D clockspeed is only applied to 'proper' fullscreen applications).

[sj33]

I had another play with it tonight. I deleted my page file and created a 4GB fixed page file (I normally do this anyway to avoid fragmentation, so Iwas surprised I hadn't done this already). I also lowered my resolution to 800x500 (fine on my 13") and enabled Vsync (forcing it using D3DOverrider, rather than ingame) to keep the fps at 60 or 30 depending on the scene (rather than is shooting over 60). All was in vain, it still happened after 20 minutes or so, and lasted 3 or 4 minutes until the fps fixed itself.

I did notice that I can tell when it's going to happen, because the fps readout spasms between 10 and 60fps super-fast, so fast that there's not actually a noticable change in framerate. Then it decides to take a dive.

I'm really lost. The only other 'exotic' thing I have set up on this computer is RMClock, to undervolt as well as manage the multipliers. I'll try it withj RMClock disabled, but seeing as it runs at maximum multiplier when the game is running, I don't see how it could be that. It's not a problem having to take 3 minute breaks now and again offline, but it's a major problem online. I'm half-tempted to format and reinstall, but I'd rather not for obvious reasons.

[Psyduck]

I remember having something similar happen years ago, but I'm not convinced it's the same thing. MS office (97?) had hard drive indexing enabled by default, and it would run regularly, and make games stutter for a while. not suggesting it's office 97, but is windows or anything else doing something similar? Does your hard drive thrash (whirr a lot!) when the game slows down?
Sounds like it's something else running in the background anyway...