Benq Service/Factory Menus, VT tweaks, XLX2720Z AMA Low

Adjusting BENQ Blur Reduction and DyAc (Dynamic Acceleration) including Blur Busters Strobe Utility. Supports most BenQ/Zowie Z-Series monitors (XL2411, XL2420, XL2720, XL2735, XL2540, XL2546)
Ozzuneoj
Posts: 42
Joined: 13 Oct 2016, 13:35

Re: Benq Service/Factory Menus, VT tweaks, XLX2720Z AMA Low

Post by Ozzuneoj » 10 Feb 2022, 13:36

So, I've been noticing lately that my XL2720Z has had a serious reduction in fine-detail clarity since I reapplied the VT tweaks. It just dawned on me that in the nvidia control panel it is showing the output color format as YCbCr422 (though still showing 8 bit), meaning 4:2:2 chroma. When I switch to a normal, non-tweaked mode it switches back to RGB (also 8 bit) and everything looks fine.

What's the deal with this? I'm using a DisplayPort cable to an RTX 3060 Ti in Windows 10 with current nvidia drivers. I forced the VT tweaks with CRU because this allows me to continue using nvidia DSR (where as adding a custom resolution with the nvidia control panel removes this capability).

EDIT: When I apply the same settings through the nvidia control panel it stays in RGB mode so the image is still clear but it drops to 6bpc even though I'm under 360Mhz? *sigh* This is still the same issue I reported almost 5 years ago with my GTX 970 and I assumed it was a GTX 970 issue since their displayport functionality was bugged. Apparently that's not the case. If I use the 1350 VT tweak I get full RGB 8bit with my 3060 Ti, but I also get a really nasty horizontal line during motion.

I like the motion clarity of this display but fighting with these settings for the past 6 years to avoid crosstalk has been a huge time sink. I wish there was something legitimately better out there.

Falkentyne
Posts: 2795
Joined: 26 Mar 2014, 07:23

Re: Benq Service/Factory Menus, VT tweaks, XLX2720Z AMA Low

Post by Falkentyne » 11 Feb 2022, 04:30

Ozzuneoj wrote:
10 Feb 2022, 13:36
So, I've been noticing lately that my XL2720Z has had a serious reduction in fine-detail clarity since I reapplied the VT tweaks. It just dawned on me that in the nvidia control panel it is showing the output color format as YCbCr422 (though still showing 8 bit), meaning 4:2:2 chroma. When I switch to a normal, non-tweaked mode it switches back to RGB (also 8 bit) and everything looks fine.

What's the deal with this? I'm using a DisplayPort cable to an RTX 3060 Ti in Windows 10 with current nvidia drivers. I forced the VT tweaks with CRU because this allows me to continue using nvidia DSR (where as adding a custom resolution with the nvidia control panel removes this capability).

EDIT: When I apply the same settings through the nvidia control panel it stays in RGB mode so the image is still clear but it drops to 6bpc even though I'm under 360Mhz? *sigh* This is still the same issue I reported almost 5 years ago with my GTX 970 and I assumed it was a GTX 970 issue since their displayport functionality was bugged. Apparently that's not the case. If I use the 1350 VT tweak I get full RGB 8bit with my 3060 Ti, but I also get a really nasty horizontal line during motion.

I like the motion clarity of this display but fighting with these settings for the past 6 years to avoid crosstalk has been a huge time sink. I wish there was something legitimately better out there.
The good old Nvidia timing issues.
The way to keep 8 BPC is to lower the pixel clock more. I found on AMD Vega 64 and R9 290X, I could run 359.94 mhz no problem and stay at 8 BPC. On Nvidia, I have to go down to around 357-358 mhz, IIRC.

Try reducing the Horizontal Total to 2001 khz (maybe 2000 works, I forgot, but I know you can't go lower). I assume this is at 120hz, right? For VT, assuming this is at 120hz, use VT 1497-1499. Check carefully when testing the VT AND HT combos, and make sure you don't get screen stuttering. You can see it clearly in Test UFO Alien Invasion, where you will either see periodic stuttering at regular 1-3 second intervals, or massive stuttering. You will also notice faint "strobe pulsing" when this happens, if blur reduction is enabled.

If you're having problems getting a stable screen, you may be able to try reduced porch and sync values, e.g. horizontal 24/3, (instead of 48/3), that may give you a bit more room to play with.

If the image is clear and smooth, make sure it remains smooth after using an S-switch profile as that refreshes the monitor, and 'bad' timings will cause the strange frameskipping stutter again. You want a HT/VT combination that both 1) keeps stutter free smoothness at least 80% of the time after pressing the S-switch, and 2) Stays at 8 bit BPC.

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CubanLegend
Posts: 29
Joined: 19 Nov 2020, 23:48
Location: Hot as Hell, FL

Re: Benq Service/Factory Menus, VT tweaks, XLX2720Z AMA Low

Post by CubanLegend » 15 Feb 2022, 19:26

Ozzuneoj wrote:
10 Feb 2022, 13:36
So, I've been noticing lately that my XL2720Z has had a serious reduction in fine-detail clarity since I reapplied the VT tweaks. It just dawned on me that in the nvidia control panel it is showing the output color format as YCbCr422 (though still showing 8 bit), meaning 4:2:2 chroma. When I switch to a normal, non-tweaked mode it switches back to RGB (also 8 bit) and everything looks fine.

What's the deal with this? I'm using a DisplayPort cable to an RTX 3060 Ti in Windows 10 with current nvidia drivers. I forced the VT tweaks with CRU because this allows me to continue using nvidia DSR (where as adding a custom resolution with the nvidia control panel removes this capability).

EDIT: When I apply the same settings through the nvidia control panel it stays in RGB mode so the image is still clear but it drops to 6bpc even though I'm under 360Mhz? *sigh* This is still the same issue I reported almost 5 years ago with my GTX 970 and I assumed it was a GTX 970 issue since their displayport functionality was bugged. Apparently that's not the case. If I use the 1350 VT tweak I get full RGB 8bit with my 3060 Ti, but I also get a really nasty horizontal line during motion.

I like the motion clarity of this display but fighting with these settings for the past 6 years to avoid crosstalk has been a huge time sink. I wish there was something legitimately better out there.
Yeah I've had the same issue, the post above mine explains it quite well.

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