Acer Predator X34A G-Sync problem

iViking · 9 Dec 2016 at 13:47

I have used my brand new Acer Predator X34A monitor for a few days, but I have discovered a problem with G-Sync. With G-Sync turned ON and the frame rate capped at 100fps in Assetto Corsa (racing game, if you don't know), I discovered some frame tearing at exactly 100fps. Capping the frame rate at 99fps solved this. But I tried Nvidia's pendulum test, which confirmed that G-Sync will only work up to 99fps on my monitor.

The blurbusters frame rate test shows a valid 100hz refresh for my monitor.

So what's next? Should I send the monitor back for RMA or is there any fix for the G-Sync??

iViking · 9 Dec 2016 at 14:50

I'm not using V-Sync in the game or in the Nvidia control panel. I'm simply capping the frame rate @ 100fps in the Assetto Corsa game settings. But as I Wrote, I'm getting tearing @100fps but not 99fps in both Assetto Corsa and the Nvidia pendulum test, with G-Sync ON and V-Sync OFF.

iViking · 10 Dec 2016 at 08:38

G-Sync is supposed to work up to and including 100hz/100fps. But watching the Nvidia pendulum demo again, I get a few teared frames even at 99fps. So either the G-Sync module is faulty or the 100hz overclock is unstable.

iViking · 10 Dec 2016 at 19:43

Your comments are irrelevant, since V-Sync is only supposed to kick in beyond 100fps and G-Sync is there to handle everything within the monitors refresh rate, which is 100hz. So if G-Sync isn't working at 99 and 100fps, either the G-Sync module isn't working as intended or the monitor simply isn't capable of sustaining the 100hz overclock.

iViking · 11 Dec 2016 at 08:34

I discovered the screen tearing while playing Assetto Corsa. With the frame rate capped to 100fps in the game settings, I noticed tearing on some tracks during gameplay and replay videos. When I turned the framerate cap back down to 99fps, the tearing mostly disappeared. With the 100fps cap, the game never renders above 99,999 fps. So with a 100hz refresh rate and G-Sync switched ON, frame tearing shouldn't happen at all.

Then I fired up the Nvidia pendulum G-Sync demo, moved the slider to 100fps min./max and saw frame tearing. Moved the sliders back to 99fps and still got the occasional teared frame, albeit not the constant tearing visible during 100fps.

iViking · 11 Dec 2016 at 19:19

No, absolutely not. G-Sync works fine without V-Sync turned on.

V-Sync only needs to be turned on if your fps exceeds the maximum refresh rate of the monitor in question.

Since the refresh rate of my monitor is 100hz, I don't need V-Sync if the frame rates are capped at exactly 100 in the game settings, which is a common feature in racing simulators.

iViking · 12 Dec 2016 at 08:00

I returned the monitor and got a refund. The IPS glow on dark- and slight coil whine on really bright backgrounds pushed me over the edge. When I game, I usually sit with all the lights turned off at night, so the IPS glow/bleed really got annoying.

I originally bought one of the early "non A" X34 screens back in january 2016, and got one with really bad backlight bleed and loud coil whine. Returned it and got a refund. I then bought the supposedly "fixed" X34A for around £900 (in danish money) on Black Friday. I think I've learned my lesson now, the Acer X34A and Asus PG348Q simply aren't worth twice the price of a 16:9 monitor with QHD and G-Sync.

iViking · 12 Dec 2016 at 19:32

...Or maybe people weren't listening. The monitor was supposed to deliver smooth G-Sync performance up to and including 100hz/100fps. My monitor had screen tear running only 99fps with G-Sync turned ON. Both 99 and 100fps should have been within the operating window of a 100hz monitor with G-Sync enabled for 100% tear free gaming, which obviously wasn't the case.

I tried the older Nvidia drivers, swithching between DP cable ports on my GTX 1080 and rebooting the 100hz overclock in the monitor OSD. None of that worked, so the monitor I received clearly couldn't deliver 100fps of silky smooth G-Sync'ed goodness. If I wanted to rely on V-Sync or Fast Sync to stop tearing, I could have bought another 21:9 QHD monitor for half the price.