5850 xfire with another 5850, or 5870?

[CG_Gamer]

im looking to up my system performance in the coming months to finish off my build and im curious which would be a better option, ive heard that when you crossfire with the 5870 you tend to see bottlenecking in the 70 due to the lower clocks of the 50, but in my case im oced past the stock 70 clocks and im wondering if, in my case, cxfire with the 70 would be more effective

here are my system specs if needed:

Thuban 1090t-4ghz
HIS HD5850-910/1200
4gb ddr3@1333/6-6-6-18
rosewill 950w

p.s. looking to get another 4gb of ram here soon

 

[wa1]

Well, if you can OC your current HD5850 speed to match or even surpass HD5870 speed then you can CF it with HD5870.
Or you can buy another HD5850 and OC it again to match HD5870 speed.

 

[CG_Gamer]

so technically it going to be the same either way? thats my max overclock right there, cus i really dont feel like breakin out a pencil for this, i was just wondering if the 870 would have a better yield

 

[wa1]

Yes, it would be cheaper to buy HD5850 and OC it to 5870 speed and you can CF it with your current HD5850 (after OC).