Sudden 100% cpu usage issue with my 8935G

I've actually had this issue for a long while by now. Basically what happens is that in the middle of some game (particular games?), *completely randomly*, my cpu usage jumps up to 100% and stays there permanently until I restart the system, causing extreme lag, typing on the keyboard becomes a chore, and audio stutters like hell.

Sometimes I can play fine for hours without any issues. Sometimes it can happen 10 minutes into a game.

From what I've tested it is not caused by the following:

- Overheating. My CPU & GPU temperatures during gaming remain normal, in the 50 C range (60 max, and never above that).
- Any windows process, task manager with all processes shown shows 0% cpu usage on all processes.
- CPU throttling. I suspected this caused it so I downloaded ThrottleStop but the numbers it showed were normal and its "clock mod" fix didn't change anything.

What causes it then?

- With some fiddling with various settings, I found that DPC (deferred procedure calls) currently are the cause and use most of the cpu.

However...what's weird is that I've had this exact same issue before, with a different thing causing it. This can be a pain to explain but bear with me.
First off, when I initially bought the laptop, it ran fine for several months, until it started doing this cpu usage thing. Back then its cause was svchost.exe with the exact same symptons.

I solved that by reformatting the HDD entirely, and the system ran fine again afterwards. Then I had to reformat again due to uninstalling my video drivers (because I was trying to update them and apparently you can't do it with a switchable graphics setup). Then I managed to update the ati catalyst at least, but not the graphics drivers. Anyways, laptop ran fine for several months again. Then this started happening again.

Now when it happens DPC (deferred procedure calls) go through the roof and overload the whole computer...I'm guessing that's some kind of hardware failure.

This doesn't happen with all games though, but I'm suspecting it's possible for it to happen in multiple games too. I initially got this when playing Monday Night Combat, just now I got it in Blood Bowl Legendary Edition as well. What's weird is that now I can run Monday Night Combat fine without the issue and Blood Bowl LE causes it.

In addition Team Fortress 2 sometimes locks down the whole laptop in the middle of the game so that I have to manually restart it (as if I had a blue screen...without the blue screen), no other games do this though.

Any ideas & suggestions? I guess it is a hardware fault, but I'm unsure because some games still play perfectly fine, and I don't have any other performance issues. This never happens in Windows either, only while gaming.

Thanks for reading the wall of text.

EDIT: And the system specs if they matter:

- Intel Core 2 Duo T6600 2.2 Ghz
- 4 GB RAM
- Ati Mobility Radeon HD 4670 XT 1 GB
- Windows 7 Home Premium 64 bit

I also use the latest version of Avast antivirus and a wireless router. Sometimes disconnecting/reconnecting to the internet, or internet going down, causes the same kind of slowdown (high cpu usage), but it's only temporary, unlike the DPC issue.

 

This is usually caused by a driver- sound drivers have a bad habit of doing such a thing, sometimes wireless drivers too.
Update all the drivers you can using the most recent drivers from manufacturers' websites or other places on the net (like laptop2go).

 

Thanks, I'll try updating my sound drivers. I already have the latest ones from Acer (not that they ever bother to update them - date is from late 2009 ), so I'm going to try to install the ones directly from the Realtek website. Wireless drivers I can also try to update if I find out what model I have.

Videocard drivers I unfortunately can't update since they cause nothing but problems (won't install, won't install back if I uninstall, etc).

 

You can use sound drivers from later machines.

I install the audio drivers from the 7750g on mine.

 

New (Realtek) sound drivers seem to have fixed it, along with TF2 no longer freezing.

Although I still get absurdly high CPU usage for several minutes when my internet connection goes down for some reason, but I guess I could hunt new wireless drivers to fix it as well (I think my wireless adapter is "Intel(R) WiFi Link 5100 AGN")