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Acer XB272 240hz can't do custom 75hz custom resolution

Posted: 25 Jan 2018, 14:48
by BlazeGaming
Hi forum,

I run a triple screen setup, center monitor being an Acer XB272 240hz G-Sync monitor and the side monitors being Acer KG271 75hz free sync monitors. What I am trying to achieve is a 75hz surround configuration but I'm being limited by my 240hz monitor that does not support that resolution by default. I've tried making a custom resolution for it but screen goes blank and nothing happens, the only data I've entered while creating the custom resolution was the 75hz and everything else was left on auto. I have questions regarding my situation:

1. Is there anything else that I need to type in to achieve that 75hz res?
2. Is setting this custom resolution going to hurt my main monitor in any way? Maybe over time?

If anyone can help out, would be appreciated. Thanks

Re: Acer XB272 240hz can't do custom 75hz custom resolution

Posted: 25 Jan 2018, 17:13
by Chief Blur Buster
Force your 240Hz to support 75Hz by using a custom resolution utility.

Get ToastyX CRU, copy the 75Hz returned by EDID of the other monitor, and paste it to the 240Hz monitor.

Most 240Hz FreeSync monitors can support fixed-75Hz even though it tells you it can't.

Last Resort Trick: If failing to do this.... Create a 75Hz mode from a higher refresh rate. Occasionally you have to create the 75Hz mode with a supported mode, e.g. 100Hz or 120Hz, via a Large Vertical Total trick (e.g. 75Hz refresh rate with the 100Hz or 120Hz exact same Horizontal Front/Sync/Back/Total and the "Pixel Clock" of 100Hz -- basically padding the VBI bigger to match the horizontal scan rate of a higher refresh rate), in a worst-case scenario, whenever a monitor refuses to support standard 75Hz with standard VBI.

Re: Acer XB272 240hz can't do custom 75hz custom resolution

Posted: 26 Jan 2018, 00:14
by BlazeGaming
Hi Chief,

First of thanks for replying so quick. I've tried both suggestions with no luck, still cant get my 240hz g-sync monitor down to 75hz.

FeelsBadMan

Re: Acer XB272 240hz can't do custom 75hz custom resolution

Posted: 26 Jan 2018, 00:16
by Chief Blur Buster
BlazeGaming wrote:Hi Chief,

First of thanks for replying so quick. I've tried both suggestions with no luck, still cant get my 240hz g-sync monitor down to 75hz.

FeelsBadMan
Your 240Hz monitor refuses to run at 75Hz fixed-frequency? Ouch.

What's the next closest refresh rate your monitor successfully runs at? 85Hz?

Re: Acer XB272 240hz can't do custom 75hz custom resolution

Posted: 26 Jan 2018, 01:48
by BlazeGaming
Next is 100 :(

Re: Acer XB272 240hz can't do custom 75hz custom resolution

Posted: 26 Jan 2018, 05:56
by lexlazootin
Image

Re: Acer XB272 240hz can't do custom 75hz custom resolution

Posted: 26 Jan 2018, 10:16
by Chief Blur Buster
lexlazootin, it works on your 240Hz GSYNC?

Yes, that was my "last resort" tip -- using the Large Vertical total to trick a G-SYNC monitor into supporting unsupported refresh rates.

Re: Acer XB272 240hz can't do custom 75hz custom resolution

Posted: 26 Jan 2018, 12:21
by BlazeGaming
lexlazootin wrote:Image
Good news and bad news.

Good news: I managed to make 75hz work with those settings, thanks a lot.

Bad news: When I setup Nvidia surround it still wont let be choose 75hz maybe because its not a "supported" resolution. Is there any way I can trick it to see it as supported via ToastyX CRU? I am kinda lost in that utility, so many settings, even for NVSurround. I don't wanna do something stupid.

Re: Acer XB272 240hz can't do custom 75hz custom resolution

Posted: 26 Jan 2018, 12:29
by Chief Blur Buster
BlazeGaming wrote:Bad news: When I setup Nvidia surround it still wont let be choose 75hz maybe because its not a "supported" resolution. Is there any way I can trick it to see it as supported via ToastyX CRU? I am kinda lost in that utility, so many settings, even for NVSurround. I don't wanna do something stupid.
One possibility is that all monitors need to be exactly the same Pixel Clock in order for surround to work.

My thinking is: You may basically need very exactly the same CRU setting on all the monitors, in order for Surround to work. Because that's the only way that the graphics card can do perfectly synchronized outputs...

Unfortunately, 75Hz monitors that are limited to 75Hz, will not support VT1500, so it might be a possibility that you are now SOL...

60Hz might be the charm?

Re: Acer XB272 240hz can't do custom 75hz custom resolution

Posted: 26 Jan 2018, 13:14
by BlazeGaming
Chief Blur Buster wrote: One possibility is that all monitors need to be exactly the same Pixel Clock in order for surround to work.

My thinking is: You may basically need very exactly the same CRU setting on all the monitors, in order for Surround to work. Because that's the only way that the graphics card can do perfectly synchronized outputs...

Unfortunately, 75Hz monitors that are limited to 75Hz, will not support VT1500, so it might be a possibility that you are now SOL...

60Hz might be the charm?
Yes you are right, I managed to make NVIDIA surround work on 75 hz by using the EDID from 75hz monitor on the 240hz but the monitor goes out of range. I guess I am stuck with 60hz surround.

Nevertheless thank you both for the help given!