It's a mighty close thing, it has to be said, although if you were looking to this version to right the dubious wrongs of AMD limiting the previous shader-unlocking shenanigans then sadly you're barking up the wrong GPU.
It looks as though the shader count has been well and truly locked down. We tried multiple methods, bricking the odd Bios as we went along (thank the maker for the recovery Bios switch), of getting at those hidden shaders but nothing worked.
Unfortunately this here Sapphire Radeon HD 6950 Dirt 3 Edition is going to stay an HD 6950.
The other unfortunate thing about not being able to flash it to HD 6970 levels is the artificial locking of the clock speed to a maximum of 840MHz still in place. That means no extra overclocking speed compared with the reference design in either AMD's OverDrive or our usual favourite, MSI's Afterburner.
But wait! Like the cavalry's flag coming flapping over the horizon is Sapphire's Trixx overclocking utility. Not only does this software enable us access to tweak the card's voltage nipples, we can also push the core clock speed up to a theoretical 1,200MHz.
In practice we struggled to get a completely stable run through of our benchmarks at 1GHz, but even at a shade under the 1,000MHz mark that's an impressive overclock.
DirectX 11 Tessellation performance
Heaven 2.5: fps. Higher is better
HD 6950 Dirt 3 Ed: 15.4
HD 6950 Reference: 15.4
DirectX 11 gaming performance
Shogun 2: fps. Higher is better
HD 6950 Dirt 3 Ed – 17.3
HD 6950 Reference – 17.3
DirectX 10 gaming performance
Just Cause 2: fps. Higher is better
HD 6950 Dirt 3 Ed – 29
HD 6950 Reference – 29