XB271HU ULMB disables pixel overdrive

doggghouse

Hi everyone, I recently bought the XB271HU and am very happy with the display!  However, one flaw I've discovered is that enabling ULMB automatically sets the OD to "off", and there's no way to re-enable it except to turn off ULMB mode.  This results in crystal clear moving images, but with equally crystal clear ghosting due to the slow pixel response.  I understand in most G-Sync monitors, overdrive settings are locked to a certain value, however it's usually locked to a more aggressive overdrive, rather than no overdrive at all!

 

Is this an intentional design on Acer's part?  Or is it a flaw with the firmware?  Because as it is now, ULMB mode is not very useful... it trades motion blur with ghosting.

 

Thanks,

Nathan

doggghouse

Ok, so I'm going to answer my own question 

 

It appears that pixel overdrive IS actually on, even though it says "off" in the settings.  And it appears that it's about the same as the normal setting.

 

However, the strobing isn't calibrated very well, at least on my monitor.  It results in a lot of strobe crosstalk towards the middle and bottom of the screen.  For some reason it looks like it's tuned to have the least crosstalk about 3" from the top of the screen, rather than at the center.

 

It looks worse than it really is when I view things on testufo.com.  For moving photos, it looks pretty good except for the bottom 1/3 of the screen, where it's very blurry and has almost a double image due to the ghosting / crosstalk.  I think if the timing was tuned better (towards the middle), then it would have must less crosstalk and a much clearer picture.