Since Radeon Software Version 16.12.1 I do only get black/white noise ("ant war") when setting refresh rate to 144 hz.
I had a the same Problem before whenever I started video streaming like Amazone Prime with the R9 290 and the RX 480 using 144 hz screen.
But since upgrading form 16.11.4 to 16.12.1 I can't even set the refresh rate to 144 hz in Windows.
What i mean with black/white noise: TV Noise - Free HD Animation - YouTube
Update1: After screen went off in idle I get ant war at 120 Hz as well. Trying 110 Hz now.
Update2: Workaround: Set your refresh rate to ≤ 110 Hz or downgrade your driver to 16.11.4.
Same Problem with 17.3.2.
There are active Adapters that support DP to DVI @120 Hz in Full HD. But it costs ~ 100€. Source: https://www.reddit.com/r/pcmasterrace/comments/4m40xb/144hz_displayport_to_dvi/d3sikep
There is an older thread where an AMD-guy stated that they had to care about FreeSync when they solved a related issue: https://community.amd.com/message/2741438#comment-2741438
I read somewhere that DVI-Ports often use the same chip/converter like neighboring DP and HDMI ports. So although higher bandwidth with DP/HDMI and DVI works completely different a Displayport cable might not be a way to fix the issue.
Likely relevant specs:
XFX RX 480 GTR (RX-480P8DFA6)
VG278HE (144hz screen)
Connection: DVI > DVI (Monitor has no DP/HDMI)
Windows 10 incl. Anniversary Update
ASRock Fatal1ty H87
Ballistix Tactical Tracer 16GB
550 Watt be quiet! Dark Power Pro 10
512GB Crucial M550