Mac Pro :: MP Cpu Load Jumps?

My new Mac Pro is causing me a lot of grief lately. Using safari or firefox, when trying to stream video, the cpu load on the system jumps to 12 or 13 % on average, sometimes up to 20%. Things get extremely choppy, and it beachballs occasionally. Just using the secondary scroll wheel on my logitech MX revolution to bring up the dashboard makes it jump to around 5%. These are tasks my little crummy old laptop handles just fine (well not the dashboard, its a windows laptop). I have ten gigs of ram, but two of my sticks are having massive ECC errors (multiple thousands) and switch between being recognized as 2gig to 1gig sticks. I got the memory from OWC and am getting it replaced though. In any case, would the faulty memory cause this much of an increase in cpu load for something as trivial and streaming low-def video? Or should I call AppleCare because something more serious may be a problem? It just doesnt seem normal for a computer where everyone says that no one normally even utilizes all the power of to be struggling with such nominal tasks.