I recently changed from a Gigabyte GTX 760 to an XFX R9 290 and noticed the issues described above. I would get random blackscreens and sporadic flickering horizontal lines on the desktop. I recently changed the computer's case and power supply and it has made a marked difference in the issue. For an extended period, I was not getting any issues at all. Recently however, the cold boot blackscreen after login issue has returned once and the flickering lines are back as well.
I changed from running Crimson 16.2 to 16.3 and I even updated the bios on my motherboard from v1.11 to v2.8 (to try and test for motherboard incompatibility) and the issue is still there. Oddly enough, the card seems to behave itself if any dedicated load such as a game is placed on it shortly after booting, but until something demanding is launched, the screen has those random horizontal flickering white lines.
- CPU - AMD FX 4300 (waiting for zen to upgrade)
- RAM - G.Skill Ripjaws X 2x4GB 1600
- GPU - XFX R9 290 reference
- MB - MSI 970a-G46
- SSD - Samsung 850 Pro
- PSU - Corsair RM850x ((previously a Corsair GS700))
- CASE - Fractal Define S ((previously a Rosewill Thor V2 that had a dent in the bottom*))
- Monitor - Acer G246HL (1920x1080 via DVI)
- Peripherals: Logitech C920 camera, Razer Deathadder Chroma, Corsair K70 RGB, Steam Controller
*I primarily changed cases since the dent in the bottom of the Rosewill case seemed to warp the frame, putting stress on the expansion slots. As such the R9 290 would barely slot into the motherboard and when encouraged to do so, did not appear to make good contact with the top pcie lane on the motherboard. Also, the GTX 760 appears to have slightly warped being installed in the computer for about 2 years. In the Define S, the R9 290 slotted into the pcie lane without too much effort, though (it may just be me but) it still appears to not completely push on all of the pcie pins in the top 16x slot. I am willing to try the lower 16x pcie slot, but unfortunately I have some hard drives attached with right angle connectors to the two sata ports that are in line with that lane, and I do not have any straight sata cables to relocate those connections.
I would have RMA'd the card, but I am not the original owner and I think the warranty expired in November.
I apologize if this is not the correct place for this question.