Fractal Design Define R3 Cooling Question

[fereak]

Hello,
I'm building an PC which I plan on overclocking. It will have an i5 and a ATI 6850. I like the look of the Fractal Design Define R3 case, which has had great reviews. However, the reviews (rightly so I suppose) assess the case's cooling based on the fans included. The cooling is not the best as it is mainly designed to be quiet. Can anyone tell me how well the case can be cooled with an added fan or two? Would it be sufficient for what I need?
Thanks.

 

[Raikiri]

I imagine it'll be more than sufficient with just the stock fans, I run a clocked i5 and 5870 with no issues using 600RPM fans (albeit a different case).

However you might want to consider the Antec P280, very similar aesthetics but it's a bit bigger and should have slightly better cooling.