Bried pixelation with a hiss

[boonedoggle]

I believe this has been addressed before, but I don't recall anyone ever coming up with an explanation and/or a fix. While digitizing or just viewing footage through Premiere 6.5 on my desktop monitor, I occasionally get a brief pixelation with a hiss. It's just enough to make anything I digitize unacceptable. I've only recently had this problem on this PC, but I've had it happen to me years ago on a different PC. I never did figure it out. Please help if you have any ideas. Thanks!

Boonedoggle

 

[WizyWyg]

defrag?
other programs running?
cache is full?

 

[Akribie]

Polling of a peripheral is another possible cause. Disconnecting unnecessary USB devices sometimes helps.