First I need to retract my statement that Flock was causing all of the DPC issues I was having. It wasn’t - instead it was a much more subtle problem and I’m still not entirely sure what to do about it.

DPC’s or Deferred Procedure Calls have been intermittently bringing my laptop to its proverbial knees over the past few weeks. Initially I had blamed the social browser, Flock. After I removed it the problem persisted though (this was a pretty intermittent problem) and I have waited until know to admit I was wrong becuase I wanted to know what the heck was going on.

This morning the DPC situation arose again. I was cruising along getting some work done when suddenly my machine became unusable. ProcessExplorer told me the DPC’s were back eating up 60-80 of my CPU and there was nothing I could do to stop it short of a reboot but I really didn’t want to reboot.

I keep all of my music on an external USB harddrive and I had some background processes going that were converting some songs from one format to another but when I stopped them the DPC issue didn’t go away. I tried to disconnect the USB drive but it wouldn’t let me - windows said it was in use. WTF? I wasn’t using it.

One of my office mates was though. He was copying the install for Open Office off my share. I didn’t know that however so I just turned off the drive. Instantly the DPC problem disappeared. I started the drive back up and the DPC problem didn’t resume for a bit but then, suddenly, it was back. After stopping the drive again and then having my friend ask what was up with my drive I put 2 and 2 together. His access of the drive was causing the DPC’s.

My initial thought was that maybe there was something wrong with my external harddrive. So I copied the OpenOffice file to my internal harddrive, shared it, and then my friend tried to copy it from the new location. DPC Spike! What a pain!

I don’t know why copying stuff off of my computer would cause a CPU usage spike on my machine but for the time being I am now off the local net with my share. If anyone knows what might cause the DPC usage and how I can alleviate it while still helping out my co-workers I would greatly appreciate it!



the problem I am having is definitely related to my external hard drive and copying files from it.

Three of us in my office have the same laptop and none of us have a DPC problem normally - regardless what we are doing with them - until the external harddrive is connected and you try to copy a file off of it.

I didn’t know the cause before because I have a shared directory on the drive that people were copying from. For the time being I have just disabled the share however, eventually, I’d like to fix the problem.


Probably your video card that’s causing the DPC’s. I recently installed a new video card in my machine and would get DPC’s that would cause the computer to come to a crawl. Once the card was removed, the DPC’s disappeared. There is a lot of information on forums regarding the issue, a search of google should turn up lots of relevant results. I believe it has something to do with the GPU unit on the video card becoming too hot, either that or a driver issue with the card.