I recently installed the new Realtek audio Drivers for my Vista 64 installation only to notice that while i played Youtube videos there was a bit of slowdown during the videos.
Anyway to cut a long story short by downloading a tool called “procexp64.exe” (Process Explorer) i was able to find out that the problem came from the process “svchost.exe”. it was using up to 30-50% of the CPU time. Meaning that things were running way slower than normal.
It took quite a few hours to figure out the problem and them i found it, by disabling the ATI HDMI outout in the “DEvice Manager” of the Control panel and restarting did the problem go away. Im Posting this this for future reference by anyone who finds this page. I was using ATi Catalyist 8.12 Drivers at the time with Vista 64 and a Ati Radeon 4870 512mb graphics card.