Sudden FPS drops in games

[Edward Yee]

In recent months I've had an issue come up where after several minutes, my PC games suffer from several minutes of single-digit fps, peak ~12 fps; even mouse cursor placement during a pause menu becomes stuttery/lagging. At first I thought it was my resolution or monitor (40-inch HDTV), but this has happened even on a small, sub-20-inch monitor at 1024x768; I thought it might have to do low system partition free space, but clearing up the hard drive didn't help. So far games I've definitely noticed this in were Modern Warfare 2, Star Trek Online, Europa Universalis III Complete, and ARMA II. Any suggestions on what could be done to get smoother fps that ISN'T turning down graphics? (Didn't help in MW2.)

CPU: AMD Athlon 64 X2, ~2.6 GHz
Motherboard: Gigabyte GA-MA780G-UD3H (from the 780G chipset)
RAM: 4 GB (2x2GB)
OS: Windows 7 64-bit
Video: nVIDIA GeForce 9500 GT, 512 MB, latest drivers
Cooling: Four internal fans (in the case)

[Stark]

You thought games slowed down because your HDD was full? Why?

When it happens check your event log to see if anything was going on in the background. Is there HDD activity? What are you doing in the background? How old is your GPU and what is the temp when slowdown occurs?

Of course since its only a problem in shit games, maybe its not really a problem at all.

[Edward Yee]

Thought it had to do with the page file somehow getting fucked with, no idea why, though evidently that's not the case. I will note though that previously this was not happening with any of these games until I'd switched to the TV as my primary display (previously using the monitor with a DVI-to-VGA/D-Sub adapter), but now even the small monitor has had the same issue, at least in MW2. My FPS numbers are from FRAPS.

By "event log," do you mean through the Performance tab of the Task Manager? Not sure about GPU age or temperature, but there's no HDD LED flashing or solid, all I've open is Firefox (so as to type this), the game (for testing purposes MW2) is the big CPU hog, ranging from ~40% to ~50%. The main thing I can find so far is that when the event occurs it seems that both CPUs have a sudden jump then nosedive in terms of usage percentage; when the event ends and FPS very suddenly rises, there's another jump in CPU usage, but it comes back down to ~50-60%.

P.S. To some extent, I'm also trying to figure out whether a GT 240 with 512 MB is worth getting for $45 (until September 8th, thanks Newegg!), considering that it's the same amount of VRAM, and I have no idea how the hell to set up SLI or CrossfireX.

[Stark]

In computer management there's an event log that tracks security, application, errors etc. If something is chunking up your CPU there might be a pile of errors in there, if your driver is crashing there should be an error in there, etc.

If you're thinking about changing video card, absolutely do it. The 240 is WAAAAAAAAAAY better than the 9500 you've got now.

[Edward Yee]

Looking at the Event Viewer (in Computer Management), I see no errors within the past hour of gameplay, though 42 within the past 24 hours (mostly to do with Kernel-EventTracing and the CAPI2 "application"), and for the last hour 41 Information events... 18 of them being Desktop Window Manager, and 18 of them being Desktop Window Manager. o_O Not using an admin account though, nor is any other account logged in.