Can an Antec 900w High Current Gamer with 4 12v rails at 40amps a piece run two 580's overclocked, a 2500k probably overclocked, a dvd drive and hard drive?
Also, I have the older Antec 1200 and am wondering how cable managment would be in it since the power supply is nonmodular.
For a system with two GeForce GTX 580 graphics cards in 2-way SLI mode NVIDIA recommends a minimum of a 900 Watt or greater power supply with a combined +12 Volt continuous current rating of 62 Amps or greater and with at least two 6-pin and two 8-pin PCI-E Supplementary Power Connectors.
The Antec High Current Gamer HCG-900 with its combined +12 Volt continuous current rating of 70.8A should in theory be able to run it.
With the older Antec 1200 you would have to find room in the case to hide the unused cables so that they don't impede air flow through the PSU and within the chassis.
load power consumption with Furmark puts it at 850W already but playing games like Crysis will get it under 700W. I would get at least 1000W. As for your antec 1200w, if you have good cable management then I would stick with it. What case are you using anyway? Some cases have areas where you can hide the cables.