What is causing my video problems? (Need an expert)?

I am very comfortable with computers and this is just boggling my mind. I recently switched computers (hardware issues on my old one). This computer is better than my old on in every way (quad core 2.4 gig, 4 gig ram, 512 mb video card) and I have two issues relating to video playback:



A) I installed my old webcam (the settings are the exact same as they were on my other computer), not only is the frame rate drastically reduced, but the video lags behind the audio. This is noticed when i create videos offline and on other peoples videos (ex skype) as well. Now here's the weirdest thing: if my computer is processing really hard, (ie installing something), or if i drag a window around the screen, the frame rate of my webcam increases! I can think of no logical reason for this but im hoping it is possible a symptom of what is causing this.



B) Whenever I play any sort of video, online or off, every 10-20 seconds it hiccups.



I've all my drivers have been updated, and i've downloaded updated versions of quicktime, flash player, windows media player, divX, direct x, fddshow etc. Nothing changes. Any ideas?What is causing my video problems? (Need an expert)?
Which graphics card are you using?



Especially with Nvidia cards, the newest drivers aren't always the best. I would Google your specific card's number, something like:



"geforce 260 best driver" or something like that.



Someone on the 'net will know which drivers are better. This is often true when using professional CG packages (Maya, XSI, Max), where the latest Quadro drivers are horrible and you have to dig through the past to find ones that fix the issues.



But this seriously seems like a GPU driver issue to me, as opposed to a CPU/motherboard driver issue.