Are you trying to run surround?
Nvidia driver will not allow surround with two monitors that are run at different resolutions.
Is the Acer X34 a Gsync monitor or a traditional monitor?
If it's gsync, then it is impossible to use surround with the Benq monitor.
The X34 does not have a hardware scaler, so any resolution below native resolution will be GPU scaled and the input resolution will still be native.
Forcing 1920x1080 on the X34 will still be using native resolution.
The XL2720Z is capable of running at 3200x1800@60hz and 3840x2160@30hz, due to scaler bugs, display scaled. I don't think 3440x1440@60 is possible due to the same firmware bug that prevents 2560x1440@60hz (display scaled) from working, yet 2560x1440@61hz works perfectly.
(the Benq's maximum display scaled resolution at semi normal refresh rates is 2560x1440@115hz and this requires the absolute lowest horizontal total and vertical total possible (HT 2641 and VT 1497). One point higher and image corruption appears (exact same corruption when you try overclocking Qinx monitors to 2560x1440@120hz and get artifacts).
3200x1800@60hz only works because the same scaler bugs which make 2560x1440@61hz, 100hz and 115hz work, allow you to use the vertical total from 3840x2160@30hz, to trick the scaler into accepting the signal. However a vertical resolution of x1440 will NOT accept the vertical total value from 3840x2160 (I tried long ago).
I can try again to see if I can get 3440x1440@60hz to work on my XL2720Z but I'm 100% sure I'm wasting my time...
*and........*
Just like I thought.
Vertical total 1486-1496 = "Out of range"
Vertical total 1497-1502 (this is the magic bug that makes 2560x1440@61hz, 2560x1440@100hz and 2560x1440@115hz work ---its the same bug that lowers blur reduction strobe cross-talk at 1920x1080)
......
.......
........
.........
drumroll please !
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.
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"No signal detected"
Sorry, I tried
Hey at least you can run 3200x1800 on your Benq if you're bored.
Use these timings:
Active: 3200, 1800
Front porch 48 pixels, 3 lines
Sync width 32 pixels, 5 lines
Horizontal total: 3360
Vertical total: 2220
Refresh rate: 60hz
That Vertical total is not the default for 3200x1800.
The default VT (if I use LCD standard) timings is a nice big fat "OUT OF RANGE!"
I had to steal it from 3840x2160@30hz, which somehow, the scaler accepts (you're going to laugh if you see the "factory" menu and see what the scaler reports the resolution is, though!)
