Hi
Same problem.
I have same CPU & Mobo , I got DisplayPort to DVI adapter I bought for 8.60$ in dealextreme. (with 4 * 5 star reviews).
I changed BIOS as you did .
Doesn't work properly. ( I noticed, one time, that screen res changed to 1024 when I re-placed the DVI to the card)
Searching for a solution I saw this
http://www.amazon.com/StarTech-com-DisplayPort-Video-Adapter-Converter/dp/B0017K6BD2 And It sates so : "DP2DVI is a passive adapter that requires a DP++ port (DisplayPort++),"
Seems that Passive adapters do not provide a certain clock that DVI needs but DP 1.1 does NOT provide , thus the monitor is recognised but not display. Active adapters have a DAC ( chip) in them to provide the missing clock.
Hence I think there is no solution BUT Active Adapter ? I hope NOT, but ...
The only thing to try is to play with voltages ? slim chance
MVG 1408, 3570K, 2x4 TridentX 2400, Intel SSD 520 120Gb, Zotac GTX 660 Ti AMP! . Hitachi 7k3000 2Tb. Roccat Kone [+] , Roccat SOTA , Roccat Kave . Samsung T220P. Modded Antec Sonata 1 (in works) \m/