I upgraded my pc to an R9 380 this summer and I had no issues. Then I purchased a brand new DVI-D 24+1 Cable to replace my old HDMI. I plugged everything and I had no signal. I said "OK ..." and I download a Display Driver Cleaner (DDC) and suddenly DVI worked. After reinstalling AMD latest drivers the problem came back. I switched my monitor (Samsung Sync Master T200HD) with my older one (EIZO FLEXSCAN S1911) and the DVI worked just fine. Also, my Samsung monitor was working just fine with my older graphics card.
Thanks for your time,