Go for HD 6850 Direct CU or HD6870

The HD6870. You can overclock it a little bit yourself.

OC is an option, but I a bit worry bout the cooling HD6870.

Depends on the rest of your set up really. The obvious thing would be to say get the better faster card but would the CU be a better balance for your system ? Something else to consider would be, do you play demanding games ?
Or do you just fancy getting the CU and having a play with over clocking it  

Mactronix  

Here is my set up:
AMD Phenom II X4 955BE @3.2
Asrock 890gx Deluxe 4
Corsair vengeance 8gb cl8
Corsair TX850 V2

And yes, I do play some demanding games.
Like I said, oc is an option. I'll do if I think I need it.

Yes looking at the system i would say go with the 6870.

Mactronix  

Thanks mac  

What about XFX HD6870? It's still in my price range but this one has a better cooler.

That would be a good idea, if you can get one with a better cooler then do so

Mactronix  

I have Corsair GS 600, 1090T, 4X2GB 1800 Princo Turbom, ASUS M5A78L LE, will my current PSU be enough for crossfiring 2x 6870? Or should I replace my current 6870 for a 6850 and buy another 6850 which is definitely supported. I am not planning on overclocking and if I would overclock it would probably be by 20-30Mhz just for fun of it. Ty for reply