Sapphire Radeon 7970 Quad-CrossFire First Look Performance @ HardwareHeaven.com
 

When we originally published our 7970 content on January 9th 2011 it wasn't possible to run Quad CrossFire with the 7970 and MSI's new X79 Big Bang XPower 2 motherboard. The configuration simply wasn't enabled. That changed overnight with a new BIOS from MSI and new driver from AMD (dated 5th January) which allowed us to test 4x7970 in CrossFire.

http://www.hardwareheaven.com/review...ics-cards.html