Had to unplug that and only use the iMac display port connection connected to the ATI Radeon HD 7979. Trying to see the BIOS (post screen) was non-existent with the Thunderbolt display. Photoshop wouldn't work with graphic card acceleration support. LucidLogix Virtu MVP Software was buggy and unstable. I had nothing but problems trying to get the Apple Thunderbolt Display to work alongside my ATI Radeon HD 7970 and the iMac (display port LED monitor). Maybe it still is terrible still, but I got some good news after all this time. Thunderbolt support on non-Apple computers was TERRIBLE back then. A couple of years ago I purchased a Thunderbolt capable motherboard ( Gigabyte GA-z77X-UP5), and an Apple's 27-in Thunderbolt Display-rather than it's (now-discontinued) Apple LED Cinema display-to go along with my Apple iMac 2010 (as a dual-display setup) which I was primarily using as an LED monitor for my Windows 7/8 PC.
