Right, spent the morning down at my local retailer
Scan
We threw hardware, drivers and prayer at the machine for 3-4 hours and came to the following conclusions
The cards I have (256Mb MSI PCI-E GF6800GTO DDR3 Dual DVI) are *not* SLi compatible, they have the bridge connectors, they will allow you to enable multi GPU mode but they cant handle it without grapical corruption
We tried several of the cards, new bridge connectors, big beefy PSUs etc, but could not get it to work satisfactorily. In fact some of the cards we tried were worse!
They happened to have a pair of XFX 6800GTs waiting to be built into a pre-built machine - slotted them in and they worked properly first time. Stress tested them a bit and all looked well.
The tech dude scarpered away and updated the website there and then to:
This
Stating that the cards will not work in SLi mode - unlike the original (I saved it just in case)
Old
So - the cert list that Zebo posted:
http://www.nzone.com/object/nz...ardware_certified.html
if you have a cards that is not on that list, and you want to run Sli - I suggest you take it back. If the retailer has advertised it as Sli compatible you should have no problems.
I'm keeping my cards until next week, when scan were happy to take them back in exchange for XFX 6800 GTs.
Just wish that cert list was available when I was purchasing my components, would have saved me many hours.
As to why the GTOs arent working in SLi mode - I have come no closer to that answer.
Incidentally, scan have ~ 100 XFX 6800GTs due in mid next week (for anyone in the UK who is desperatelyt struggling to track down anything other than the GTOs)