NEW PSU

If you work thru the simple process at the link below you will be able to determine:

1. How much power your system requires now and for future upgrades

2. What 12v rail current is required

3. Read reviews on PSUs that might be available in your locale to find a quality PSU in your price range


This way you won't need to guess abut the PSU requirements, as you'll have accurate electrical information.
http://www.tomshardware.co.uk/forum/314712-10-please-re...

The ones that I would consider out of that list are:
Seasonic S12II Bronze 520 and 620W
Silverstone Strider Essential 500W
OCZ StealthXStream II 500W

All of these will be able to easily power your build and you would even be able to add another 6850 in crossfire and still be immensely comfortable.

Best answer selected by 016ive.

thanks for ur replies it really helped me out a lot thanks guyz u r the best  

sorry can i crossfire using another 6850 with 500w psu? i thought that is impossible i need at least 650w or 750w ? i don't really know u r the expert here  

6850s are not power hungry.
http://www.anandtech.com/show/4061/amds-radeon-hd-6970-...
6850 Crossfire Power Consumption:
Idle = 170W
Load - Crysis = 378
Load - Furmark = 423W
As you can see even under Furmark you wouldn't be overloading a high quality 500W PSU. Seeing as Furmark places an unrealistic load on GPUs the normal maximum power consumption won't be as high (unless of course you plan to run Furmark on a regular basis or run programs like BOINC) and typical power consumption will be much lower, thus hardly stressing your PSU at all.

I know that the Sapphire Toxic 6850 comes with two 6pin PEG connectors, but it is not necessary to have both of them plugged in.

The reason the Thermaltake Litepower shouldn't be considered is because its quality is unknown as it hasn't been reviewed, customer reviews aren't always worth the paper they're written on.
Also, on closer inspection of its power label I have discovered that the 700W unit is the 'peak' number, a wattage that is only intended to be drawn for very short periods of time. Its continuous rating is 600W. Also it's 12V combined rating is 504W. So it is no winner in the wattage stakes.

People always say that 650W is minimum for everything (even single cards) because they overestimate power consumption. A legitimate reason to go for a ~650W unit is give yourself more upgrade options in the future.

Finally I also singled out the Seasonic S12II Bronze 620W. Which gives that bit extra which would make a lot of people less nervous, even tho they'd have no reason to be nervous with a 500W unit.

thanks for illuminating this it really helped me out and i'm getting that Seasonic ( special thanks for ur reply Silvune   )