HSF and Compatibility Question

First of all, here is my current system:

ASUS M2N-SLI Deluxe
AMD Athlon X2 6400+ (Widsor)
2GB (1 x 2GB) G. Skill DDR2 800
Sapphire Radeon HD3850 512MB PCI-e
500GB Seagate Barracuda
Raidmax Smilodon w/500W PSU

I'm thinking about upgrading to a Phenom X4, probably a lower clocked one like the 9650, and then OC'ing it. I'll probably ebay my Athlon X2 to help finance the Phenom. My first question is, if I keep the HSF from my Athlon, will it be sufficient for a Phenom? That would allow me to purchase an OEM Phenom (I'm a bit short on cash). I am pretty sure that the Windsor Athlons shipped with the same stock HSF as the Phenoms. Am I correct? I realize that I probably won't be able to get much of an OC with a stock HSF anyway, but for now, I just need to get by. Secondly, does anyone here have any experience with using a Phenom with an M2N-SLI Deluxe? I know they should be compatible with a BIOS update, but I've read good and bad on various forums. Thanks for any help or suggestions.

And I know somebody is going to say I should upgrade my graphics card instead, but I'm very happy with my 3850 for now. I just got it a couple weeks ago (couldn't pass up the "shell shocker" deal) to replace an 8600GT, and I don't plan on upgrading again any time soon.

that is down grade unless your multi point acess server or some type of multi threaded software user

yuk!