Modded Radeon HD 6950 and regular HD 6970 power consumption test under FurMark
The Radeon HD 6950 and Radeon HD 6970 are based on the same piece of silicon (the Cayman core). The differences between Cayman PRO (HD 6950) and Cayman XT (HD 6970) are the clock speeds and the number of shader processors. Cayman XT has 1536 SP while Cayman PRO has only 1408 SP. In the Cayman PRO, 128 SP (or two SIMD –one SIMD is made up of 64 SP) have been disabled in the VGA BIOS.
techPowerUP has a complete guide about how to unlock the 128 SP of the HD 6950: AMD Radeon HD 6950 to HD 6970 Mod.
The good news is that all current HD 6950 can be modded. What’s more, if you set HD 6950 clock speed to match HD 6970 ones, the HD 6850 has the same performance than a full HD 6970.
But it seems that the mod is not complete because PowerTune is not upgraded by the BIOS flash. So to fully take advantage of the modded HD 6950 with HD 6970 clock speed, you have to set the PowerTune to +20%.