Hey I got an old optiplex gx 520 from Dell and I was wondering what processors are compatible with it, I'm thinking a q6600 or even a core 2 duo to replace the Single Core Pentium 4 HT 521. My "decent" PC came up with a problem I didn't notice from day 1 of my build...All I'm gonna do on this PC is browsing and watching some videos. But the Pentium makes it A LOT harder, I can't even watch 480p video properly. Thanks in advance dudes