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Re: I got my new Acer Predator XB272 G-Sync in today!

Posted: 28 Jul 2017, 17:13
by RealNC
lexlazootin wrote:ULMB (Single Strobe) also works at 60hz, all you need to do is use the 100hz timings and simply boost the VT to 1900 and set the Hz to 60.
Does the monitor support 85Hz ULMB? In that case, try using 85Hz timings instead of 100Hz; might give you even less crosstalk.

Re: I got my new Acer Predator XB272 G-Sync in today!

Posted: 29 Jul 2017, 00:34
by lexlazootin
Na, 85hz isn't a thing on this monitor.

240, 200, 144, 120, 100, 60

Re: I got my new Acer Predator XB272 G-Sync in today!

Posted: 01 Aug 2017, 15:18
by Chief Blur Buster
RealNC wrote:
lexlazootin wrote:ULMB (Single Strobe) also works at 60hz, all you need to do is use the 100hz timings and simply boost the VT to 1900 and set the Hz to 60.
Does the monitor support 85Hz ULMB? In that case, try using 85Hz timings instead of 100Hz; might give you even less crosstalk.
Many 240Hz ULMB monitors only support ULMB at 100Hz, 120Hz and 144Hz.

Basically, removes the 85Hz ULMB and adds 144Hz ULMB.

However, it's apparently possible to trick ULMB to work at non-standard refresh rates on certain models (not all of them) via the Vertical Total trick. Unfortunately the Vertical Total trick may not improve strobe crosstalk like it does on some BenQ/Zowie monitors.
lexlazootin wrote:ULMB (Single Strobe) also works at 60hz, all you need to do is use the 100hz timings and simply boost the VT to 1900 and set the Hz to 60.
When you do this, how does strobe crosstalk change if you change VT via Front Porch, or VT via Back Porch.

I think your strobe crosstalk will shift upwards/downwards somewhat at http://www.testufo.com/crosstalk .... Does it look better if you increase VT via Back Porch, or increase VT via Front Porch in ToastyX's Custom Resolution Utility to do the 60Hz ULMB trick?

Re: I got my new Acer Predator XB272 G-Sync in today!

Posted: 02 Aug 2017, 06:55
by lexlazootin
I'm not able to change it enough to have any significant an impact, if any at all. the highest i could get was like 63 front.

Re: I got my new Acer Predator XB272 G-Sync in today!

Posted: 03 Aug 2017, 22:28
by sharp
On this review they say the G-Sync range is 60-240 for this monitor...

http://www.mmorpg.com/hardware-reviews/ ... 1000011920

Is that true? I would expect it to be 30-240.

Re: I got my new Acer Predator XB272 G-Sync in today!

Posted: 04 Aug 2017, 02:25
by RealNC
sharp wrote:On this review they say the G-Sync range is 60-240 for this monitor...

http://www.mmorpg.com/hardware-reviews/ ... 1000011920

Is that true? I would expect it to be 30-240.
I would expect it to be 60 really. Or even 120-240. These fast panels should be difficult to drive at lower refresh rates.

Why does it matter though? Even if the panel range is 60-240, the effective g-sync range is still 0-240.

Re: I got my new Acer Predator XB272 G-Sync in today!

Posted: 04 Aug 2017, 04:19
by lexlazootin
Yea i'm not sure what the point of having a minimum is since it will go down to 0. But yea, it will go to 30 and below @sharp

Re: I got my new Acer Predator XB272 G-Sync in today!

Posted: 04 Aug 2017, 11:03
by Chief Blur Buster
The newest drivers/implementations (of GSYNC/FreeSync) have various forms of low-framerate compensation algorithms, which will help smooth out VRR motion below the panel's VRR rate as well, by simply adjusting the timings of repeat-refresh cycles to get virtually exact (in theory) "refresh cycles" below the minimum Hz. e.g. Refreshing three times at 72Hz in order to achieve 24Hz.

Re: I got my new Acer Predator XB272 G-Sync in today!

Posted: 04 Aug 2017, 13:26
by jorimt
sharp wrote:On this review they say the G-Sync range is 60-240 for this monitor...

http://www.mmorpg.com/hardware-reviews/ ... 1000011920

Is that true? I would expect it to be 30-240.
Hmm, that doesn't seem right at all. I tested the XB252Q thoroughly in my G-SYNC 101: Input Lag & Optimal Settings article, and G-SYNC worked well below 60Hz.

Perhaps they mean the lowest physical refresh rate it supports is 60Hz in the Nvidia Control panel?

I know the minimum refresh range usually starts at <36Hz on 144Hz G-SYNC displays, but I'd have to have something like an oscilloscope to test when it starts on these 240Hz model, and I don't have one handy.

I can't imagine why the minimum refresh range wouldn't start lower than 60Hz though.

EDIT: Not concrete proof, but the XB252Q user manual states 30-240Hz range on DP:

Image

FYI, refresh rate and scanout speed/time aren't the same thing. Just because the lowest supported scanout appears to be 60Hz on the 240Hz XB252Q, G-SYNC should be able to refresh the screen below that Hz.

With G-SYNC, refresh rate = number of refreshed cycles per second, and maximum set Hz = how fast each refresh cycle completes. Again, not sure when the minimum refresh range is triggered on these 240Hz displays though.

Re: I got my new Acer Predator XB272 G-Sync in today!

Posted: 17 Aug 2017, 04:33
by Sumeri
lexlazootin wrote: G-Sync + ULMB (Lightboost?) does in fact work at 144hz! or even 145hz if you overclock it a little :P
G-Sync + ULMB work out the box or some tinkering is required?