weird issue mixing 60 and 144hz monitors (dual setup)

BlueBanana · July 27, 2016

I recently switched from 3 old displays to a dual-setup with a Benq XL2720Z (1080p, 144hz) and a Benq BL2710 (1440p, 60hz).

The 1080p one connects via DVI-D and the 1440p (after getting a "no signal" with Displayport ) via HDMI.

Now I encountered something really weird:
When the 1080p is set to run at 144hz, the 1440p one feels reeeeally laggy. Scrolling and marking text for example has really noticeable delay, making the monitor feel very unresponsive.
Setting the 1080p one (!) to 60hz gets rid of the issue. Oo

(issue persists with 120hz)

What's going on? How can the refresh rate of one display has an effect on the responsiveness of the other one?
Any Ideas how I can address the problem?

My rig:
Display 1: Benq XL2720Z
Display 2: Benq BL2710
VGA: Asus GTX 970
CPU: i7 3770
RAM: 16GB

BlueBanana · July 29, 2016

On 27.7.2016 at 8:14 AM, ScootsMcgoots said:

I dunno, but when I had a 144hz one an a 60 hz one dragging windows around looked supper laggy .

yeah pretty much everything is very unresponsive.

So here's my theory after researching a bit:

Maybe the GPU cannot output two different refresh rates so that the 60hz monitor also gets 144hz. Why everything would get laggy and unresponsive - I don't know.

Just a theory, don't know if it's true.

Thony · July 29, 2016

When u see 144Hz and 60hz side by side then it does look super laggy because u got used to look at 144Hz and just realized how shitty the 60Hz is.

Since u dont game on both u could connect that 1440p to your iGPU (if u have one) and let the 144Hz have the whole GPU for itself

I notice that 60Hz is shittiest but I don't experience any unresponsiveness.

BlueBanana · July 30, 2016

20 hours ago, Thony said:

When u see 144Hz and 60hz side by side then it does look super laggy because u got used to look at 144Hz and just realized how shitty the 60Hz is.

Since u dont game on both u could connect that 1440p to your iGPU (if u have one) and let the 144Hz have the whole GPU for itself

I notice that 60Hz is shittiest but I don't experience any unresponsiveness.

It's definitely unresponsive. Very unresponsive. Also there's a very noticeable difference when I set both displays to 60hz. So it's unfortunately not the realization that 60hz is shitty compared to 144hz.

I don't have a iGPU, but I couldnt use it anyway, because I use the 1440p for work where I need the cuda cores of the nvidia GPU. (mainly Adobe stuff, quite a difference to non-cuda)