I am building a dual xeon system using 2 Xeon L5410's that I got for free. I plan on using a Supermicro X7DCA-L-O and adding 12 GB of Kingston DDR2 ECC ram along with a HD 4850 Vid Card, and a SATA dvd burner. I will also re use a case and hdd. My question is will a Antec 550 watt powersupply be enough to run the system. Another question is about heatsinks that will work with socket 771, I need suggestions on good heatsinks. Thanks for the advice.