BenQ XL2720Z overclocked to 220Hz and 250Hz [SUCCESS!]

Talk about overclocking displays at a higher refresh rate. This includes homebrew, 165Hz, QNIX, Catleap, Overlord Tempest, SEIKI displays, certain HDTVs, and other overclockable displays.
naso
Posts: 2
Joined: 09 May 2020, 21:41

Re: BenQ XL2720Z overclocked to 220Hz and 250Hz [SUCCESS!]

Post by naso » 09 May 2020, 21:42

I can't get mine over 179hz.

https://i.imgur.com/LM5QZyP.png

Kulagin
Posts: 36
Joined: 27 Feb 2016, 08:17

Re: BenQ XL2720Z overclocked to 220Hz and 250Hz [SUCCESS!]

Post by Kulagin » 14 Oct 2020, 11:42

loopy750 wrote:
20 May 2019, 04:00
250Hz was achieved by setting both vertical porch and sync to 1, as due to the DisplayPort bandwidth limit, that was really pushing it to the limit - maybe even slightly too far - and I wouldn't recommend it.
Is it 250 Hz at 1080p? With what settings exactly did you manage to run it at 250 Hz?

How did you manage to go over 480 mHz DisplayPort limit?
When I set resolution in CRU and go over 480 mHz:
Image

This refresh rate refuses to show up in the list of refresh rates:
Image

222 Hz with these settings shows just fine because it doesn't go over 480 mHz:
Image

Is it me or is it the same for everyone and it just stops showing up in the list if you create a resolution over 480 mHz?

Kulagin
Posts: 36
Joined: 27 Feb 2016, 08:17

Re: BenQ XL2720Z overclocked to 220Hz and 250Hz [SUCCESS!]

Post by Kulagin » 14 Oct 2020, 11:43

loopy750 wrote:
20 May 2019, 04:00
Not to mention how much worse YCbCr422 looks compared to RGB, IMO, which is why I consider 220Hz the practical limit, and somewhere between 240-248Hz if YCbCr422 doesn't bother you.
I don't have any settings like this. Does it use YCbCr422 automatically when you go over some bandwidth?
loopy750 wrote:
20 May 2019, 04:00
It does make you wonder how much higher the monitor could potentially be overclocked if not bandwidth limited.
I managed to make it work alright at 262 Hz(DisplayPort and DVI-D with ToastyX's pixel clock patcher) without frameskipping using these settings:
Image

Then at 263 Hz it black-screens.

Also managed to make 264 Hz work with these settings:
Image

But it's flickering and is not really usable.

I'd prefer to use 250 Hz @ 1080p than these settings, I don't know how to make refresh rates over 480 mHz appear in the list.

loopy750
Posts: 10
Joined: 16 May 2019, 10:50

Re: BenQ XL2720Z overclocked to 220Hz and 250Hz [SUCCESS!]

Post by loopy750 » 14 Oct 2020, 13:34

Kulagin wrote:
14 Oct 2020, 11:42

Is it 250 Hz at 1080p? With what settings exactly did you manage to run it at 250 Hz?
Yes. I'm really not sure how. I'm using a DisplayPort cable and NVIDIA graphics card. What could different to your setup is I'm using Zowie V008 firmware and Zowie XL display driver (BENQ display driver makes no difference though). Is that what allows me to go to 540MHz, or is it something else? I really don't know.

These are my settings at 1080p using a DisplayPort cable, pushed to the limit (540MHz?)

file.png
file.png (29.16 KiB) Viewed 279 times

Just noticed you're using an AMD card. I assume that has something to do with it... maybe someone else can confirm?

Falkentyne
Posts: 2602
Joined: 26 Mar 2014, 07:23

Re: BenQ XL2720Z overclocked to 220Hz and 250Hz [SUCCESS!]

Post by Falkentyne » 17 Oct 2020, 16:51

loopy750 wrote:
14 Oct 2020, 13:34
Kulagin wrote:
14 Oct 2020, 11:42

Is it 250 Hz at 1080p? With what settings exactly did you manage to run it at 250 Hz?
Yes. I'm really not sure how. I'm using a DisplayPort cable and NVIDIA graphics card. What could different to your setup is I'm using Zowie V008 firmware and Zowie XL display driver (BENQ display driver makes no difference though). Is that what allows me to go to 540MHz, or is it something else? I really don't know.

These are my settings at 1080p using a DisplayPort cable, pushed to the limit (540MHz?)


file.png


Just noticed you're using an AMD card. I assume that has something to do with it... maybe someone else can confirm?
I haven't tested higher than 165hz because 6 BPC looks like total garbage. Might be ok in some FPS games (you get the same issue with 125hz with a VT 1497-VT 1502 tweak (range due to certain VT's frameskipping), due to pixel clock > 359.99 mhz. Blur reduction does work however, although the crosstalk sucks.

I would honestly like to try 220hz with blur reduction enabled, but I have a feeling MBR won't work at all, or trying to use it will either cause the monitor to power cycle trip or no backlight.

BTW Something I noticed which may help some of you.

The "Strobe persistence" base settings, depends on the resolution you used BEFORE switching to 165hz. This is important.
For example, at 60hz, the persistence settings are 0.167ms per point of strobe duty. At 120hz it's 0.83ms and at 144hz it's 0.69ms.
If you have a VT tweak active, example, at 120hz/100hz, VT 1500 for instance, this forces the monitor to use the 60hz strobe pulse widths (0.167ms). That's another reason why the monitor is brighter when you use a VT Tweak, and the "maximum" strobe phase before the backlight shuts off is reduced (100hz=phase 059, 120hz=phase 049, 125hz=phase 047 I think are the "Cutoff points" when using a VT Tweak). When you use 165hz, it seems like the strobe pulse widths are the ones used BEFORE switching to 165hz! This sort of makes sense, since the firmware doesn't recognize 165hz.

This is important ONLY if you are using blur reduction. A 60hz strobe pulse width at 165hz will have the monitor EXTREMELY BRIGHT at a strobe duty of 008 (almost as bright as 120hz with VT 1500 active at strobe duty 030 !! Note that 120hz with strobe duty 030 is nowhere near as bright), which comes very close to the trip point where the monitor will power cycle from over-driving the LEDs! I recommend no higher than a strobe phase of 005 for normal daytime blur reduction if you are switching "from" a 60hz strobe persistence pulse width with a VT Tweak active, and 004 for no background light nighttime.

If you switch from 144hz to 165hz and MBR is very dim, it will use the 0.69ms pulse widths and you will probably need a strobe duty of 015 for decent brightness. If you try strobe duty 015 if it's using the 60hz strobe pulse widths, the monitor will probably instantly power trip. And if it doesn't, you're risking damaging or destroying the backlight so be careful. Start with Strobe Duty 006 to be safe. If it's super bright with MBR on, it's using the 60hz pulse widths. If it's very dim, it's using "default" pulse widths.

I have NOT tested whether this "bug" happens if you switch from a standard refresh rate without a VT Tweak active (e.g. 60hz stock, 100 hz stock, 120hz stock), as I have VT tweaks for reduced crosstalk for everything except 144hz.

I also don't know if higher vertical totals at the 165hz setting will work for reducing strobe crosstalk or not. I'm 99% sure already VT 1500 definitely won't work (even though you can get the pixel clock down to like 450 mhz by reducing the front porch and horizontal total). VT 1350 may or may not work. Haven't tried; most likely the monitor would either refuse to sync at all or would display complete garbage on the screen. If someone wants to try and see if crosstalk reduction works on "Test UFO, Alien invasion", be my guest.

Has anyone used blur reduction successfully at >180-220hz?

Kulagin
Posts: 36
Joined: 27 Feb 2016, 08:17

Re: BenQ XL2720Z overclocked to 220Hz and 250Hz [SUCCESS!]

Post by Kulagin » Yesterday, 14:33

Falkentyne wrote:
17 Oct 2020, 16:51
I haven't tested higher than 165hz because 6 BPC looks like total garbage.
I keep reading about 6 BPC and 8 BPC but it looks exactly the same at 144 Hz and 222 Hz. Here are photos:
Image
Image

They look exactly the same on camera and for my eyes.

Though, it does show 8 bpc at 144 Hz and 6 bpc at 222 Hz:
Image
Image

When I started reading about that it looks bad, I was expecting 6-bit RGB, something like this:
Image

But it looks just fine as you can see on the photos above.
Last edited by Kulagin on 21 Oct 2020, 14:46, edited 1 time in total.

Kulagin
Posts: 36
Joined: 27 Feb 2016, 08:17

Re: BenQ XL2720Z overclocked to 220Hz and 250Hz [SUCCESS!]

Post by Kulagin » Yesterday, 14:39

Falkentyne wrote:
17 Oct 2020, 16:51
Has anyone used blur reduction successfully at >180-220hz?
Yes, works just fine at 222(1920x1080) and 264 Hz(1600x900) for me:
Image
Falkentyne wrote:
17 Oct 2020, 16:51
I would honestly like to try 220hz with blur reduction enabled, but I have a feeling MBR won't work at all, or trying to use it will either cause the monitor to power cycle trip or no backlight.
Didn't experience anything like that yet.

I'm on V4 firmware.

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