am planning to get myself an hd5850 graphics card as soon as it is available. but am having a CM extreme power 500W spms now and it has only 1 4-pin PCI-E power connector while 5850 requires two 75W 6-pin PCI-E power connectors. please specify the least expensive power supply that can power a 5850 and meet my power req... my system spec : C2Q 9550, MSI P45, 1TB+(500x2)GB HDD, 2x2GB DDR2, etc should a corsair 550W be enough??? if not which one should i go for???