Enabling 4K on HD6870 with mDP to DP cable Dell P27

0

Im not able to get the resolution over 1920x1080 on the Dell P2715Q, while using 22" via DVI, and another 22" with miniDV to dvi. I haven't tried without the other two disconnected yet.

What i did try https://superuser.com/a/894800/287677 still cant even get over the 1920x1080, its black backlit, with no mouse only before auto power-out. I also have the 2160p already as a choice in windows, not sure if the CRU step is necessary being this.

So then i tried making custom settings in CRU like 2560x1440 at various refresh rate, namely 30,60, and 59.996 none of which work either. I had verified it was patched, then was no longer able to run dell monitor tool after, said i needed supported monitor.

Lastnight I rolled back the clock rate override, uninstalled dell drivers, put back in default, still the dell manager "no workie" said i didn't have supported monitor.

Today, an update must have fixed the OEM, or couple reboot, because now all 3 monitors are back on working in full, but at the 1080p res only.

How can i get at least 1440p out of this? Could it be because the other two monitors? Am i missing something?

One 22" on DVI next to minidv's, the other 22" uses an "active" adapter on a minidv, then the P27 uses the other minidv out(from the HD6870).

Catalyst version 2015.0804.21.41908

Brian Thomas

Posted 2017-01-11T04:06:29.630

Reputation: 161

Are you daisy chaining? What happens with just the Dell? – Journeyman Geek – 2017-01-11T04:28:31.983

Not daisy chaining, and not sure yet, havent tried. not easy to get to equipment. – Brian Thomas – 2017-01-11T09:32:38.013

I got it to work without the hack, by disconnecting the other monitors, it worked out of the box. Add an answer please, just please add the mandatory fact that you need to disconnect possibly, and also, what i did was i had to connect the minidv from the very left, to the one closer to the middle actually, once i did that, it immediately went to 2160p without even touching any settings. THe other monitors where then able to connect up, successfully running 22/22/27. I might try to test if im now getting 4k, and apply the hack from here. – Brian Thomas – 2017-01-11T23:04:40.627

Answers

1

Bit of guesswork here - I admit I assumed it was some MST related oddness, and suggested that plugging in one monitor would force the video card to identify it and to set the best mode for it.

Since the 3 monitors were set to 1080p - my guess is the driver reinstall set things to use eyefinity, and the lowest common denominator among the three - which the documentation seems to confirm.

The OP also indicated that what i did was i had to connect the minidv from the very left, to the one closer to the middle actually, once i did that, it immediately went to 2160p

Not sure whether the ports are different somehow.

If it happens again, check eyefinity settings to see if that's the case.

Journeyman Geek

Posted 2017-01-11T04:06:29.630

Reputation: 119 122

Asked: 2017-01-11T04:06:29.630

Viewed: 120 times

Active: 2017-01-12T09:52:16.027