I flashed the Vapor X to 7970 Bios 1100 - 1450 (Sapphire)
Then I OCed to 1100 -1600 stable at 1.056 Volts
Unigine *8 *16 Extreme Tess
1224 (48.6 av - 26.1 low - 119.9 high)
An Nvidia GeForce GTX 680 2GB @ 1006 - 6008 scores 46.6 @ 1080 same settings (I presume @ stock).
3D Mark
GRAPHICS SCORE
8626
Not too bad... and total stable without a voltage increase.
http://www.tomshardware.co.uk/charts/2012-vga-gpgpu/01-3DMark11-B-Performance,2932.html
The Sapphire Radeon HD 7970 Toxic 6GB Lethal Boost is rated at 8421 (I guess its not clocked!!!). I'm happy with the card now.
It really needs the new bios.
It runs @ 76 degrees under load.
I'll be buying a waterblock for it before I volt it up.