cant get 4k monitor working properly

Icyseanfitz

ok this has me stumped as i dont know all that much about monitors, i recently bought a aoc u2868pqu which runs natively at 4k. Heres where it gets a bit weird, in order to get 60hz refresh rate you need to use a displayport 1.2 cable, I bought a mini dp to dp 1.2 cable and connected it all up to my amd 7970.

It runs 4k and 1080p at 60hz which is great, only problem is that i was hoping to use 2560x1440 at 60hz until my gaming rig got a nice update next year, unfortunately i cant seem to get that resolution working at all through the displayport cable. Whenever i try to select a resolution between 1920x1080 and 3840x2160 i get black borders around my desktop, the icons etc. stay the same as if i was using 4k but i get black borders (See attachment).

Whats odd is that all the resolutions seem to work ok if i use hdmi but i can only get 30hz

i havnt really tried any of this out in games but my desktop isnt working right so i presume it wont work for games.

Any help would be great as ive no idea at this stage :pac:

challengemaster

Sounds like its an issue because 1440p isn't a native resolution, whereas 1080 and 4k are. So it's resorting to borders to run 1440.

Since you're using ATI/AMD graphics card, take a look in catalyst control centre for scaling options (underscan/overscan). Play with that and you should be able to set 1440p and then adjust the scaling to match the display size.

Icyseanfitz

not getting any scaling options in Radeon settings (just updated so this must be the new ccc) good god this is confusing

challengemaster

http://www.anandtech.com/show/9811/amd-crimson-driver-overview/4

I'm basing my answer off of reading the above on the new crimson drivers - I don't have an ATI card. It looks like you need to go to display options and then click on the Additional settings button in the top right.



Then you'll have scaling options in the list on the left

Icyseanfitz

yeah im trying to figure out why im not getting those scaling options at the moment, im getting all those options except for scaling is it something to do with using a display port to mini display port? when i had it connected via hdmi it had scaling options and all the resolutions worked as intended but i was stuck at 30hz
thanks for trying to help me out with this one, im generally pretty good at troubleshooting but this has my head in bits

had updated to the newest driver so im going to see what happens if i roll back to 15.7.1

challengemaster

What makes the U2868PQU particularly interesting, however, is the fact that it can handle 4K resolutions via DisplayPort at 60Hz using Single-Stream Transport (SST). Readers who have been keeping a close eye on 4K developments will know that earlier displays utilised Multi-Stream Transport (MST), forcing the initial batch of 4K panels to be recognised by the OS as two, or more, displays tiled together. Such a setup was hardly ideal, and the new scaler technology built into the AOC panel is a marked improvement - hook it up via DisplayPort and it's instantly recognised as a single 3,840x2,160 panel with a 60Hz refresh rate.

DisplayPort 1.2, then, is the connection of choice, however HDMI 1.4 (with MHL compliance), DVI and VGA inputs are also provided, though do be aware that using either HDMI or DVI limits refresh to 30Hz.

That's the reason you're getting stuck at 30hz using HDMI, it's because its HDMI 1.4. So is your 7970, if you check the specs it can only output 4k @ 30hz anyway over HDMI.

Scaling options apparently don't apply to DP for some reason, so thats why it's not showing.

Seems that it could be the cable at fault.

Icyseanfitz

anyway of fixing the issue? or should i try to get a different monitor? only have this around a week, I really do like it but no 2k gaming at 60hz kind of ruins it tbh, tried the witcher 2 there at 2k and i was getting the same letterbox effect

challengemaster

Try a different cable first, maybe from a different manufacturer.

If you could try the monitor on a different system - one without using a mini DP adapter, just straight DP to DP. In all honesty I'd say the monitor is not the problem here.

Icyseanfitz

il buy another cable (display port cables are super pricey though ) sure if it doesnt work i can just game at 1080p until i build my super rig sometime next year and just game at 4k, thanks for all the help, much appreciated

Cuddlesworth

Why not set the main res to 4k and then set the games to 1440p full screen.

Icyseanfitz

Already tried that, it gives me a letterbox style effect where it considers what it's outputting as full screen even though I've massive black bars on all sides

Icyseanfitz

ok this has gotten even bloody weirder i tried checking my resolution with a few online checkers while running at 4k (3840x2160) and my results are coming back as 2949x1658 :mad: what is going on is the monitor faulty or the cable? i tried with the hdmi and got the same result

mordeith

Icyseanfitz wrote: »

ok this has gotten even bloody weirder i tried checking my resolution with a few online checkers while running at 4k (3840x2160) and my results are coming back as 2949x1658 :mad: what is going on is the monitor faulty or the cable? i tried with the hdmi and got the same result

The zoom level of your browser affects the result. My laptop is at 1920 x 1080 but that site reports it as 1536x864. If I reduce soom level to 80% it reports 1920 x 1080.

Icyseanfitz

its the custom dpi i put my screen at to make icons/font look bigger in 4k that throwing it off for some reason

ED E

Icyseanfitz wrote: »

its the custom dpi i put my screen at to make icons/font look bigger in 4k that throwing it off for some reason

Yes, that would thorw it. Changing DPI essentially scales back the effective resolution.