The Sapphire Radeon HD 6950 Dirt 3 Edition's a reference GPU and no mistake. There's absolutely no difference in clock speeds, and hence no change in performance. What's not shown in the raw fps numbers, however, is the change in temperature.
The three small and two fat heatpipes do a fantastic job of pulling the GPU sweat away from the chip. It idles around 10C cooler and manages a 12C drop in temperatures under load. That, however, does come at a higher cost in terms of power draw – it's 30W more thirsty than the reference card.
Sadly, however, no matter how much of an overclock you can squeeze out of this little GPU, it's no substitute for the reference chip's shader-unlock prowess. And no matter what, it's always going to be compared to that.
The fact you can get around AMD's artificial locking of the Cayman Pro's core clock speeds is an absolute bonus for this Sapphire card. It makes for some serious overclocking chops.
The new cooler is also impressive, giving a hefty drop in temperature to help push along that overclocking prowess.
Sadly one of our favourite things about the reference HD 6950, the shader-unlock, has been cut out of the latest round of Cayman Pro GPUs, making the dual-Bios almost irrelevant now.
That new cooler has also had a rather negative effect on the power draw too, making for a fairly significant extra pull under load.
If you look at this Radeon HD 6950 Dirt 3 Edition with an open mind, and no thought to the shader-unlocking loving, then you wont be disappointed. It's one of the best stock HD 6950s out there, and one of the coolest too.