Going from P4 630 to PD 915

Hey all
I do allot of multi-tasking and some gaming and my present P4(3.0G) is pretty lousy @ multi-tasks. Was wondering if i went to PD915(2.8G), that i can get for pretty cheap,would make much of a diff. seein as im going to a true dual core. Thanx.
Specs:
HP media center PC m7257c
P4630(P)HT 3.0GHz
Asus P5LP-LE Phoenix bios V3.17
2Gb(4x512) PC2-3200 3-3-3-9
250GB SATA
16XDVD DL Lightscribe
19" LCD
XP pro media SP2
XFX GeForce 8600 GT XXX
Corsair 550 VX