Nvidia Adaptive Sync issues HP 27xq + 2 secondary monitors

[TehJumpingJawa]

I’ve recently purchased an HP 27xq, and when using Adaptive sync I’ve encountered occasional screen blanking that’s apparently a result of my setup including 2 secondary monitors.

My setup is thus:

Zotac GTX 1070

• DP output to DP input of the HP 27xq (1440p 144Hz freesync enabled)
• HDMI output to the DVI input of a Dell U2412M (1920x1200 60Hz IPS)
• DVI output to the DVI input of a 2nd Dell U2412M.

It’s worth noting that this setup worked fine with my previous gaming monitor (An AOC G2590px; 1080p 144Hz freesync officially ‘g-sync compatible’), and I was expecting the HP 27xq to be a straight forward drop-in replacement/upgrade.
However this clearly isn’t the case =(

To reproduce the blanking behaviour, I just leave the Nvidia Pendulum test running for a minute or two with the framerate range set to 20-144.
Though I’ve also experienced the blanking while playing The Witcher 3, so it’s not just a synthetic issue.

I’ve tried all sorts to try to either correct, or workaround the issue:

• moving the HP 27xq over to different DP ports on the graphics card.
  No Effect

• swapping the Dell monitors over to using:
  – passive DP -> HDMI (->DVI)
  No Effect
  – active DP -> VGA
  Drastically increased the blanking.

• using CRU to edit the EDID of the HP 27xq, to:
  – decrease the lower bound for adaptive sync to 30Hz (default range is 48-144Hz)
  Drastically increased the blanking.
  – increase the lower bound for adaptive sync to 60Hz
  No Effect, or perhaps reduced (but not eliminated) the blanking.
  – adjusted the refresh rates of the Dell monitors. (Several values within the 50-62Hz range)
  Significantly increased the blanking.

• Switched my 1070 for a Palit 1060 3GB.
  No effect. Must either be a driver issue, a cabling issue, or a flaw inherent to all Pascal GPUs.

• Connected my 1060 3GB to spare pcie x1 (via a janky x1 -> x16 mining adaptor), with the intent of using it to drive the Dell monitors, leaving the 1070 to exclusively drive the HP 27xq.
  Wasn’t stable (I suspect poor contacts were causing the 1060 to drop off the bus).

• Disabled both of the Dell monitors.
  Blanking fixed!

• Disabled the Dell monitor connected via HDMI output.
  Blanking fixed!

• Disabled the Dell monitor connected via DVI output.
  Blanking fixed!

• Tested various lower resolutions on the Dell monitors (perhaps reducing collective bandwidth usage?)
  No effect, or significantly increased the blanking.

• Swapped one of the Dell monitors for my AOC G2590px (@ 1080p 144Hz via HDMI)
  No Effect.

At this point I’m running out of things to try, and would welcome suggestions as I’m beginning to believe it’s impossible for an Nvidia GPU to use adaptive sync with the HP 27xq while simultaneously driving two other monitors.

My last remaining idea is to connect the Dell monitors via DP->DP. However this will require me to buy a couple of DP cables, and I’m doubtful it’ll fix anything. It might even make things worse as I’ll be mixing DP 1.1 signals (Dell monitors) with DP 1.2 (HP 27xq).

If all else fails, I’ll return the monitor as faulty… which would be a shame, as it was an excellent price & in most other regards is excellent.

[johnw1]

I am having the same issue. I did not see that monitor listed on the nvidia list of “compatible” G sync monitors. Mine is also not listed and this could a part of the problem.

I am running just a single monitor. It’s a Asus VG249Q 1080p 144Hz. I have it connected via DP to a GTX 1070. When I enable G sync it will intermittently blank the display for 1-2 seconds and then come back. I can correct the issue by disabling G Sync.

I do have my Vive plugged in via HDMI. It is in standby but I wonder if that could be Interfering with the g sync protocol.

[TehJumpingJawa]

Tried a few more things with a pair of new DP1.2 cables.

• Connected all 3 monitors via DP.
  No change.
• Switched the cables around so the HP 27xq was on a cable known to be DP1.2.
  No change.
• Swapped out my entire PC (Win10x64, Ryzen 2700, 1070), for a different one. (Win10x64, Ryzen 1600, 1060 6GB).
  No change.

As swapping out;

• the cables
• the computer
• the secondary monitors
  still results in the exact same issue it seems highly likely that this is either a fault with the monitor’s FreeSync implementation, or a fault with Nvidia’s ‘g-sync compatible’ implementation of it.
  Unfortunately I don’t have an AMD card with which to test the latter possibility.

Hope this information comes in useful to anyone else running into trouble when pairing the HP 27xq’s FreeSync with an Nvidia GPU and multiple secondary monitors.