4870s

[Prototype]

I would get a new Corsair power supply.

But if your new monitor isn't at least 1920x1080 then Crossfire won't be needed.

 

[stb1swat]

haha. Well we'll see.

 

[baron5]

Don't worry you will be fine, that psu has 17 and 18A rails and even thought it's not gonna be 80% efficient it will definitely be enough to run a single 4890/4870 if you were to get one. But of course if you want crossfire you will need to upgrade. It's not worth buying a whole new psu just for one gpu upgrade.