Honestly this could be the decision maker as to whether or not I would get a 4850 or a 4870. Because in my particular build, going with a 4870 (1GB) would REQUIRE aftermarket cooling, as well as modification or replacement of the bracket. This is because my board is BTX, and all of the 1GB 4870s require an open slot for cooling which I do not have. Now, if I need to also replace my PS, the cost will definitely be so much as to go with a 4850.
Anyway, the power supply is an Antec SmartPower 500W. It has dual 12V, one is 17A (204W) and the other is 19A (228W). Current processor is a 2.4GHz Core2, but may eventually upgrade to a 3.46GHz Core2. Memory is going to be 3GB PC5300 for now, and drives will be an 80GB SATA 300, and a 250GB SATA 300. There will be an optical drive, and a SATA PCI controller card as well.
Theres other details to work out too if I want to go 4870, but for now my question is if my power supply will handle it.
I have heard that the 4870 uses 160W, so each 12V line surpasses that. Thanks for any help in this decision. I am really excited to get this system running some Halo 2, Crysis, and X-Plane.
The long answer is the card requires 2 PCI-E connectors and if you don't have them available you will need to use molex to PCI-E adapters. If you do decide to use adapters you will need to make sure you aren't overloading either of the rails, keep in mind there are other things connected to each rail other than just the video card. If you could determine which PSU cables are fed by each rail you could split the video card power between them and you would be fine.