Hello, I have little to no experience when it comes to DPC, but I've been having this problem with my laptop this month which seems to have arrive "out of the blue". I noticed it this week when I got completely random FPS drops whilst playing Left4Dead, so I looked at the Task Manager and realized that every short fps drop correlated with l4d's cpu usage dropping for a 1-2sec, but nothing was using that. I booted up Process Explorer from sysinternals and found out that every drop correlated with DPC using a large amount of cpu then dorpping back to 0. To sum it up it seems that because L4D uses nearly 100% cpu on both cores, it gets a stutter when DPC "steals" from it. I did research on DPC and used the Windows Performance Analyzer tools (xperf) to log what's using and here are the results: After playing L4D for a little bit to log these incidents, here's the table for DPC Usage: ...and the graph: I can upload the log if needed. Was made with a xperf.exe -on DiagEasy I thought maybe there is a problem with some USB appliances so I unplugged them all and that usage went away, but I still got stutters ingame. Any ideas/opinions?