Overclocking the HD 5850?

[Prayd41]

I recently built a PC with a diamond HD 5850 and I am considering OCing it from GPU clock 760 and memory clock 1050 TO GPU clock 850 and memorcy clock 1200 (5870 stock standards). The thing is I am completely new to overclocking and the only reason I want to is that I cant play crysis at enthusiast settings at a resolution of 5870x1080 (although I can at 1920 x 1080). I want to be able to play crysis 2 maxed with the 5870 res, so I am guessing I am going to need to OC, am I rigt?

So am I going to need an aftermarket cooler to OC it that much. Right now the temps get to about low 60sC with crysis warhead at gamer settings at 5870 x1080 res.

 

[Prayd41]

Forgot to list my specs in case that helps:

CPU: AMD Phenom II X4 965 BE @3.4Ghz
Memory:OCZ Gold Tri Channel 6144MB PC10666 DDR3 1333MHz
Mobo: MSI 870A-G54 AMD 870 Socket AM3
GFX: Diamond HD5850
Case: Antec Nine Hundred Black Steel ATX Mid Tower Case
PSU: Corsair 650TX
OS: Win 7 Home Premium 64

 

[shening]

to play crysis maxed at 5870 res you will need more than a OCed 5850...like at least two 5850s

 

[supersnicker]

Overclocking a 5850 to 5870 speeds will not make it as fast, the 5870 has more stream processors (1600 vs 1440). http://www.bjorn3d.com/read.php?cID=1702 is a tutorial you should definately check out, as it takes every aspect in detail.