Hi, I am just wondering what two Geforce 460's would be equivalent to in SLI and what PSU I would  need? I was also wondering if SLI causes many problems? I was going to get a 3meg Geforce 580GTX, but they are STILL so expensive. Thankyou!!Last I used an SLI rig performance was about 30% more than it would be with a single card. Don't know if that improved much over the years.
Might want to just read some reviews where they do tests.Personally I would just keep your 2 460's and wait for the prices to go down.  Dual 1GB 460's are comparable to 1 580 3GB right now.  If you really wanted, get ONE of the 580's and later on consider doing an SLI.  One 580 on a good system should overkill everything you throw at it right now.  Once it starts to show age, a second one will breathe new life into your system at that time.Crafty,

I'd go with the 460's right now also. A 500 what Power Supply should be fine for those cards. Just make sure the power supply has the pci-e power connectors for the cards.

MichaelThe 460's will offer less video memory than the 3gb 580. But this really has no downfall unless you're playing DX11 games in high resolutions with Anti Aliasing. Check out this link, this website actually pits two GTX 460's in SLI vs one GTX 580 and then explains the pros and cons: http://www.hardocp.com/article/2010/12/02/geforce_gtx_580_vs_460_1gb_sli/3Thankyou all for your replies I really appreciate it, but I have decided on going for a geforce 570 GTX. I have found that my TOWER is a little on the small side for SLi at present and that is something I'll have to upgrade next. I decided on the Evga super overclocked Geforce 570GTX and looking at it's performance, it's not to far behind the Geforce 580GTX, and it's a little below two Geforce 460GTX SLi on performance. My thinking behind this is that the Geforce 570GTX will come down in price much more then the Geforce 580GTX, and when I SLi two of these cards TOGETHER I should have a performance of the scale  . For now though the card plays all the games I play on high settings and I'll look to get a game like metro when I have two of these cards. Anyway let me know what you think of the Geforce 570GTX as a good purchase, I got this card for a good price of £260 since most other places were selling them at £280 - £300 plus.I think the EVGA GTX 570 SC will suit you just fine  I have always been a fan of EVGA and I just got the EVGA GTX 560 SC a month or two ago. I have yet to find a game that I couldn't play on highest settings with 1920 x 1080 res. Good Choice with the 570 SC!