I have this psu in my other rig, it is a ok unit but far from perfect, I think that you will be able to get by but that is only by a margin knowing how this unit isn't their best. Runs rather hot well mine any way. Power wise the GTX460 isn't a hog till you start pushing the card to 900mhz+ then each could draw over 200w depending on the quality of each sample and the physical varm on each card.
I'm using that psu myself, with everything o/c. I had my doubts,
It runs fine, and have never had a weird 'event'.
I used Y splitters to avoid the whole molex (possible complications)
I use Everest and HW monitor to peek at the power rails and nothing 'bad' happens.
The rails do drop slightly lower than I have ever seen them before the 2nd gtx 460, but not more than .1 http://www.newegg.com/Product/Product.aspx?Item=N82E168...
is out of stock. Its sleeved and a little nicer, but this will work as well, you would need 2. To turn your 2 pci-e connectors to 4 http://www.newegg.com/Product/Product.aspx?Item=N82E168...
The PSU, does not seem to run warm. I do not have a hot environment and I don't usually run Furmark. But I have and ran Prime 95 at the same time. It all ran fine.
So there are no disadvantages to using a PSU with multiple +12V rails?
No! I wouldn't say that at all. To illustrate potential problems, I'll use these two examples:
An FSP Epsilon 700W has ample power for any SLI rig out there, right? But the unit only comes with two PCIe connectors. The two PCIe connectors on the unit are each on their own +12V rail. Each of these rails provides up to 18A which is almost three times more than what a 6-pin PCIe power connector is designed to deliver! What if I want to run a pair of GTX cards? It would have been ideal if they could put two PCIe connectors on each of those rails instead of just one, but instead those with GTX SLI are forced to use Molex to PCIe adapters. Here comes the problem: When you use the Molex to PCIe adapters, you have now added the load from graphics cards onto the rail that's also supplying power to all of your hard drives, optical drives, fans, CCFL's, water pump.. you name it. Suddenly, during a game, the PC shuts down completely.
Solution: To my knowledge, there aren't one-to-two PCIe adapters. Ideally, you'd want to open that PSU up and solder down another pair of PCIe connectors to the rails the existing PCIe connectors are on, but alas... that is not practical. So even if your PSU has MORE than ample power for your next graphics cards upgrade, if it doesn't come with all of the appropriate connectors, it's time to buy another power supply.
When this post was written by a very knowledgeable engineer , the Y splitters I pointed out to you, were not widely available.