you're lucky I'm a cheif mod on another Tech help forum...

Its always a good idea to shut down other apps while capturing video, as it eats your CPU like crazy, even with 2GB of RAM, and a fast proc, you should still close the other apps.

The thing about Dual core processors is that they have exactly that, dual cores, eg - 2 cores, each running at the described clock speed. If I were you, I'd consider going for a quad core really.