Want to upgrade my memory on my Dell XPS420 desktop. I ran a scan at Crucial to see available upgrades. They offer either 5300 or a 6400 options. Crucial says if my processor has an "FSB" speed that can handle the 6400's, they would be faster/better option. My question: my processor is Intel 2 Quad Q6600 @2.40 GHz 2.39 GHz , how do I determine what its FSB speed is? Thank you !