XB271HU ULMB disables pixel overdrive

doggghouse
doggghouse Member Posts: 3 New User
edited February 2024 in 2018 Archives

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

Answers

  • doggghouse
    doggghouse Member Posts: 3 New User

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

     

    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.

  • consumedsoul
    consumedsoul Member Posts: 1 New User

    I just got mine today, so what setting(s) did you end up going with in the end?

  • doggghouse
    doggghouse Member Posts: 3 New User

    I just left ULMB off, and run with G-Sync enabled and the pixel overdrive (OD) setting at default (normal?).

     

    I prefer having access to G-Sync anyway, and when games are running at 100FPS+, it's still TONS clearer and smoother looking than a 60Hz display.  It seems that the latest IPS panels can't really keep up with ULMB, because the pixels are still trying to transition when the strobe lights up, so you're left with a double image for half of the screen!  Before this Acer, I had an ASUS PG278Q, which has a TN panel, and a super fast pixel response time... ULMB mode worked great with no double image!  But it had its own issues, which is why I ended up selling it for the XB271HU.  I rarely used ULMB mode on my PG278Q anyway...

  • PanzerIV88
    PanzerIV88 Member Posts: 1 New User
    Hi guys,

    I know I'm replying to this thread EXACTLY 2 years later lol but I just received today that same monitor from Amazon in Canada and unfortunately I got to say I have all the same issues that you are experimenting. I paid almost 200$ less cause I took an open box unit with 1 tiny dead pixel in the top-left corner that's pretty much invisible anyway, but still it is unacceptable at such a crazy high price-tag to have such bad ULMB and it was one of the Top 3 reasons I was buying this monitor as it is usually better than G-Sync if you can maintain a constant 100FPS+ which I can with my GTX1080.

    I compared side-by-side against my (BenQ XL2730Z) and while crosstalk is overall better, the fixed trail "ghosting image" is extremely annoying and there are no such thing on the BenQ. I expected better from the IPS panel as they said it was the fatest on the market with 4ms blablabla so I didn't thought only +3ms over my TN would make such a difference.

    I've seen people using G-Sync + ULBM at the same time on BlurBusters so I'll have to see if both together can be a good compromise cause otherwise I might just return it. It is also darker with ULBM than the BenQ, and I don't even have the newer and brighter XL2735!