Monitor: Dual Link DVI-D
Cables: Both Dual Link DVI-D and Single Link DVI-D
HD5870: Dual Link DVI-I
If this helps.
I found out this isnt just a 5870 problem, ive searched the endless seas of the web and found many with this problem dating as far back as 2005.
Same problem with my old X600 DVI videocard.
Im beginning to think its software related.
Windows 7 64bit is the OS.
I guess i'll also add, that this no signal thing isnt IN Windows. I cant see system info such as BIOS or POST...as well as Windows.
Installed Windows XP SP3, still the same thing.
One thing is different:
I installed XP while i was using HDMI > HDMI on my TV (Since that works fine). When i plug in the additional DVI > DVI to my Monitor, the ATI Drivers, and the CCC (Catalyst Control Center) detects that there's another monitor plugged in, but i cant enable it. When i do, it just refreshes the screen, and its back to disabled. Same think for when i go into Desktop Properties>Settings and try to enable the monitor.