I've been having a problem with the flash plugin this year. I'm not sure when it started exactly, but I'm certain that this wasn't happening during 2011.
When at a site that uses Flash for video+audio (Youtube and similar) or even audio-only playback (Turntable, Pandora, etc), I find that the flash plugin causes spikes of 100% CPU usage (on one core) and that the video or audio will pause for a moment during those spikes. The disruption is typically in the 100-500ms range.
Frequency of the spikes seems to vary over time. It's fairly typical to experience a situation where it starts off bad and the frequency of disruption lessens over the course of 30 minutes until there are no disruptions at all. If you keep using playback, it'll work its way into being bad again. You're likely to start using the flash plugin at any point on that sine wave of disruption intensity. It might start working well but slowly get worse, it might start bad and slowly get better, it might start at a tolerable level and work its way worse or better depending on if you're on the rising or falling side of the cycle.
Whatever it is, it isn't my Windows install. I switched from an AMD FX-8120 to an Intel 3930K about a month ago and this problem persisted through new hardware and a fresh install of Windows using the latest device drivers for everything. I've even tested different browsers in case it was an issue with only the non-IE plugin or with my specific browser (Opera). The issue happens in Chrome, IE9, Opera, and FF on my system. I've also tested both with and without hardware acceleration, but there is no difference.
I have to wonder if there are any known issues with particular sound cards (Xonar STX), unusual video configurations (dual Radeon 6970s in crossfire), or peripherals. Perhaps with output sampling rates (96 KHz) or security software like MSE?
Anyhow, I mention this here in the hope of either raising awareness of a problem or finding answers if this is a known issue. It's silly that playing back audio would be a challenge in 2012 with good equipment. There is sure to be a logical explanation that can help lead me to a resolution. Thank you.