I see this is not exactly a fresh thread, but even with a lot of DPC latency issues out there being documented, it seems that tracking down the cuase is a science in itself! I've never had any issues until I installed my new gigabyte GTX 460 - along with which came a new driver (1st version for this card). Now, I've been having issues when playing back music and, as it would appear, surfing the net and using keyboard. Yup, that's right - that's the only 'reproduceable' cuase... Need Foobar2000 open, along with a browser (IE, Chrome, FF, doesn't matter), and I have to be typing or clicking, and then the popping sounds start left and right. Stop typing, and it's all under control. Now, the interesting part is that nothing else changed in my system but the video card and its driver. All other stuff (hardware and software) are all the same as before and I had no issues at all - zero! Odd eh?