You do eliminate 1 advantage of large vertical totals, but you still have another advantage:Falkentyne wrote:13 Mar 2021, 18:35Got my XL2746S today from Amazon. Never ordered a monitor on amazon before, it was always Newegg. And I know about all the horror stories of dead pixels and IPS lotteries and eventually people getting "banned" from Amazon so I was worried.
Anyway looks like I "won" the panel lottery. Can't find any dead pixels. Panel seems as flawless as my XL2720Z (so far).
Messed around in the Service Menu
DyAC High and Premium seem to just have a different brightness? I did notice that when changing one, the strobe phase and strobe duty (Area and intensity) seem to reset to a saved value, there seems to be a value saved for each setting.
Monitor seems to have the "VT 1500" tweak built in (aka accelerated scanout), just like Lightboost mode. Strobe crosstalk at 100hz and 120hz are literally identical to the XL2720Z with a 1500 tweak (I compared it pixel by pixel), so no 100hz/120hz VT Tweak is even needed, with the exception that you can't shut off the backlight by raising the Area too high (to where it clips into the persistence range). Raising the Area to 100 doesn't quite drop the crosstalk field to the very bottom (I assume that's' because on the XL2720Z/XL2420Z etc, increasing the Strobe Phase when a VT tweak is active limits the maximum strobe duty, e.g. Phase 049 on XL2720Z with VT Tweak limits max duty to 001 (dimmest). So most likely, being able to lower the crosstalk field lower than the position Benq allows at "100" Area would limit Intensity to values higher than 1, and that would be a customer service nightmare, so i can see why that's capped there.
Vertical Total tweaks still reduce input lag via the Quick Frame Transport effect. Large Vertical Totals force the visible part of the refresh cycle to be transmitted faster over the DisplayPort cable, so it can be refreshed sooner, so that the strobe backlight can flash sooner.
For example, VT1500 means the refresh cycle is delivered in only 1080/1500ths of a refresh cycle (of the current Hz). If you're using VT2250 (which works on the XL2746S at 120Hz), you reduce DyAc strobe lag by up to about 4 milliseconds.
There are multiple benefits of large Vertical Totals, even if the monitor is scan-converting. The problem with automatic large vertical totals in the monitor is that it has to buffer VT1125 to do internal VT1500 or something like that on the panel (see diagrams, so you can avoid this buffering behavior by making sure your external VT is at least as big as the internal VT -- even if there's no crosstalk quality differences.
(This is what 240 Hz BenQs do by default for low-Hz modes like 60 Hz or 120 Hz)
(This is what you can get your 240 Hz BenQ to do)
With large VT's, more refresh cycle is transmitted more quickly sooner on the cable, before being refreshed onto the panel,
The easiest way to create a Quick Frame Transport mode is this one:Falkentyne wrote:13 Mar 2021, 18:35Possibly a VT tweak may allow crosstalk to be lowered more than the default value (e.g. each point of Area may lower the crosstalk more pixels than the "default") but I haven't tested this yet. I was only doing a "dry run" on my laptop's mini DP port to check for dead pixels.
OD Gain is funny.
It goes up and down by values of 1, in hexadecimal. You can adjust exactly how much ghosting "amount" you want, although it cant be removed fully. You can turn the UFO ghosts totally completely purple if you want. OD Gain=00 is like overdrive is disabled.
I doubt I can hack 60hz single strobe on this. (e.g. by tricking the monitor into thinking it's running at a higher refresh rate). I tried it on my XL2720Z and it still double strobed at 85hz and lower. I'll try a custom resolution made for 120hz and try lowering the refresh rate without changing the other timings but I think the monitor is too smart for me. Not doing this now. Maybe later.
Chief Blur Buster wrote: Optional ~4ms reduction in strobe latency for 120Hz strobe on 240Hz monitors
There's up to a 4ms strobe latency savings if you decide to hit two birds with one stone.
<Optional Advanced User Tweak: Quick Frame Transport>
Geometrically, the pixels are delivered left-to-right, top-to-bottom over a cable from GPU to monitor -- in this order in this pixel layout for all screens, per refresh cycle.
Like reading a book or a calendar, pixels are delivered one at a time over a video cable (VGA, HDMI, DVI, DisplayPort) at the pixel clock speed. The porches/sync intervals are spacers between pixel rows and between refresh cycles.
So this diagram is repeated 120 times on the cable for 120 Hz refresh cycles -- in the art of delivering 2D pictures over a 1D wire.
But How Do We Deliver a 100Hz or 120Hz Refresh Cycle In 1/240 second?
There are ways to speed up delivery of individual refresh cycles over a video cable requires a large blanking interval (vertical sync/porches), which can compress the transmission of the active visible refresh cycles to a shorter time period (e.g. 100Hz refresh cycle transmitted over DisplayPort in 1/240sec).
This helps strobing lag a bit because pixels can be delivered faster, and refreshed onto the panel sooner, to allow the strobe backlight to flash a bit sooner -- up to about 4ms sooner (for 120Hz 8ms refresh cycles delivered in 1/240sec 4ms delivery)
The most applicable FAQs are Custom Resolution Utility glossary, as well as Quick Frame Transport.
The most common 120Hz QFT timings is as follows:
From Advanced XG270 Tweaks.
This reduces PureXP latency by about 4ms at 120Hz.
Math Calculation For Other Refresh Rates
Most 1080p signals use a typical Vertical Total 1125 (1080 visible rows + 45 spacer between refresh cycles as blanking interval). After putting the radio button on the "Total" you can usually calculate your ideal QFT VT by multiplying 1125 by 240 then dividing by your preferred refresh rate. At 100 Hz, you can use (1125 * 240 / 100) = VT2700 at 100Hz. Just keep all 240 Hz ToastyX numbers unchanged when changing vertical total and refresh rate (the only two numbers that should change). Make sure horizontal refresh rate is exactly unchanged and make sure pixel clock (dot clock) is exactly unchanged, versus the original working 240 Hz mode.
1. Start with a working default max-Hz mode
2. Put radio button on "Vertical"
3. Put radio button on "Pixel Clock"
4. Don't edit any other number except "Vertical Total". Increase Vertical Total and you'll see Hz automatically decrease.
5. Now you have a large-VT low-Hz mode derived from your working max-Hz mode.
More advanced information can be found at Quick Frame Transport thread.
</Optional Advanced User Tweak: Quick Frame Transport>