E4600 or E6400?

[Terry33]

Hi! I'm a newbie in this site. I just want to seek the expert opinions of your readers pertaining to my upgrade plan. I want to replace the ageing P4 531 Prescott chip of my kid's desktop with either a C2D E6400 or C2D E4600 in Asus P5PE-VM motherboard and also wanted to install a Geforce 6200 AGP card just to spice up the old system with light gaming. Based on my research the board can accept a 1066mhz FSB 2.13Ghz C2D E6400 by OC if the AGP card will be used but the DDR-400 RAM will downgrade to 355mhz due to chipset limitation, while the higher clocked 800mhz FSB 2.4Ghz C2D E4600 does not limit the RAM. Now my question is: Which of the 2 chips perform much better? I'm more inclined to go for E4600 but I'm confused because I can't use the AGP card anymore. Is there a way that I can still use the AGP card even with 800mhz FSB CPU to be installed? The Asus website tells a different thing. If not, then I have to settle with E6400? Please help. Any suggestions or recommendation shall be appreciated. Thanks!