XFX HD 6950 won't go over 500 MHz under max load

[cipitiox]

Hi, i recently purchased an used xfx 6950, HD-695X-CNFC, off of ebay for $150. It turns out that the max core clock only hits 500MHz under full load. I've used msi afterburner and gpu-z to check frequencies and they all show max 500MHz instead of the stock 800MHz under BF3 max settings load.

Is there anything wrong with this card, how can i accurately measure the core clock?

I was thinking about RMAing the card to XFX as the ebay seller doesn't accept returns.

If not i'll just resell this card and get a 660ti from msi, N660Ti PE 2GD5/OC

Rig
Gibabyte GA-Z77X-D3H.
i5-3570k @4.3
intel ssd 520 120gb
XFX 6950, HD-695X-CNFC
Corsair CX 650 PSU
Corsair Vengeance 8gb @1600
Windows 7 64 bit
dell u2410 monitor

 

[cipitiox]

I just ran a 3d mark 11 benchmark and it showed that a 450MHz on the core clock. It also said that my computer scored lower than it should... Any ideas on what's wrong with this card?