Some good news

After contacting MSI support they have got back to me with a new bios (1.7B5) and it has fixed the problem.
The board and card are now working correctly together.

It's definitely a bios problem as I had been given some new drivers to try which didn't help at all but the bios certainly did.

If any GD70/5870 owners need access to this bios pls PM me.

http://service.futuremark.com/result...eResultType=19