I have a 4K Philips monitor (BDM4065UC 40", 4k) and bought a Sapphire RX 470 this week.
Without any driver i am at 64 Hz at Ultra HD (3840*2160)
After installing 16.9.2 (or 16.9.3 beta) i only have 30 Hz at that resolution.
It is not a matter of the cable (high quality DP cable). I had a Geforce 980 Ti before and there were no problems. Even with the Intel CPU graphics i had 60 Hz at ultra hd.
This seems to be a driver problem?
How can i solve this?
i am aware, that the 470 is a step down - i don't have the time for hardcore gaming, so the 470 with full hd power is enough in the near future
ofc the monitor is already on dp 1.2
i quote myself :-) "It is not a matter of the cable (high quality DP cable). I had a Geforce 980 Ti before and there were no problems. Even with the Intel CPU graphics i had 60 Hz at ultra hd."
terrible drivers so far - i had only 24 hz an hour ago even on 1080p
Sometimes people forget to recheck settings after(new card/driver/windows install will sometimes reset to default native res.).
What OS ?.
amdmatt may have other suggestions.
OS is Windows 10 Pro.
Yesterday evening it worked once. 60 Hz at ultra hd, but it is now at 30 hz again.
I installed the tool from this thread:
The custom monitor setting in the crimson driver won't help too, since it tells me, that my monitor won't support the resolution with the 59 / 60 hz and is not compatible (which of course it is)
i started in safe mode and uninstalled all old driver with the "display driver uninstaller"
then i intalled the newest (beta) crimson driver
still no change :-(
The 980 doesn't fully support Full fat UHD playback, this is well documented, it compresses the colour space, it has limted bandwidth, 10gbps I think.