Okay so what is this 1502 tweak I keep seeing around here?!

[TwentyFoe]

I was the guy who confirmed V2 XL2420Z from Amazon (the sticky post), and at the time (and to this day), everytime I visit this page, the VT tweak mentioned is 1350, and this is what I've been using.
What is this 1502 tweak you guys keep mentioning? I Googled it and searched around but couldn't find the origin/source or any other explanation...

Thanks!

[Falkentyne]

http://forums.blurbusters.com/viewtopic.php?f=13&t=560

Except at 60hz refresh rate, anything that doesn't go out of range at higher than 1260 VT, will work between 1498 to 1502 VT.
If 1502 VT gives 'pulsating' image and flicker stutter movement (e.g. this happens randomly at 120hz refresh rate mode set, but if it does not happen, it's fine until the next refresh rate change or screen power on/off), then VT 1500 will work.

If VT 1500 gives stutters/pulsating, then VT 1498 will always work (e.g. 85 hz refresh rate).

And higher Vertical totals (default is 1125) trick the monitor scaler into extending the duration of the blanking interval (from around 0.5 milliseconds to between 2.4 milliseconds), which effectively gives the panel more time to complete a full pixel transition across the screen while strobing in blur reduction mode, effectively lowering the crosstalk at the bottom of the screen.

The actual effect is the monitor scaler gets 'tricked' into refreshing a larger screen blank area. You can only see this by entering the factory service menu in version 4 firmware. With a VT 1502 tweak, the scaler thinks the vertical size is 1440 instead of 1080.

By comparing how far the crosstalk has moved DOWNWARDS, you can see that the increase in vertical size between 1440 and 1080 is 33% (360 lines) (the scaler is reporting a resolution of 1280x1440 instead of 1920x1080).
This is very close to the 377 difference between 1125 and 1502 which is 377, then the percentage increase (difference in 1502-1125) divided by 1125, then that multiplied by 100, is sure enough, 33.5%.

http://www.skillsyouneed.com/num/percent-change.html

So the 33.5% increase in vertical total (1125 to 1502) matches the value the monitor scaler reports (1440 instead of 1080).
Ignore the horizontal width of 1280....the scaler pulls that number out because it tries to find a matching resolution with a similar aspect, but can't.

The net effect is, the bottom area crosstalk shown in THIS test:

http://www.testufo.com/#test=photo&phot ... &height=-1

is moved downwards around 33% lower if you compare (do this at 100hz), the default 100 hz at 1125 vertical total, versus the 100 hz at 1502 vertical total. (pretend you had a vertical screen size of 1440 lines instead of 1080 lines, and the remaining were "off screen" at the bottom), it matches right up.

To do a VT tweak, you need ToastyX custom resolution utility (you can do it with the NVidia custom res utility also), and the AMD or Nvidia pixel clock patcher (if the pixel clock exceeds 330.00 MHz).

the monitor scaler won't accept a scaler screen width size of higher than 33%. It will just go out of range.

The reason why the OSD reports 60hz refresh rate (The V4 service menu shows 1280x1440@60) is because the scaler sees a 'new' resolution due to the change in vertical total, that it can't identify, so it reverts to 60hz backlight pulse widths (NOT exactly the same as strobing rates, e.g. a scanning backlight refreshes top to down, but it's more complicated than that when you deal with refresh rates!-e.g. Double strobing at 60hz refresh rate is NOT the same as single strobing with a much higher "persistence." If Chief is around, I'm sure he can explain this correctly for you.

[TwentyFoe]

Thanks a lot for the in-depth explanation Falkentyne! I realize what that tweak is, or at least I understood the general idea behind it (as I mentioned, I've been using the 1350 one, and a brief explanation is also written there by the Chief). You provided some extra, so thanks for this. I'll probably give it another read again later!
I just couldn't understand how come the Chief wouldn't update it to 1502 (if it is obviously possible), but oh well! I changed mine to 1502 as well.
EDIT: Wow that guy posted this 1502 tweak back in April last year, a month before I got my monitor. So basically I have been using 1350 instead of 1502 for a whole year! But I'm assuming the difference isn't as noticeable from the original VT to 1350, right?

If you don't mind explaining something else to me... Why is it not recommended to use Blur Reduction along with 144Hz? Why are these tweaks only compatible with 120Hz? I think the Chief once answered such question, but I can't find it now.

I play CS:GO (Counter Strike: Global Offensive), and literally every one around me (in case they possess a 144Hz BenQ monitor) use 144Hz and not 120 + Blur Reduction. I am literally the only one, and I've been wondering if I should just switch to 144Hz as well, because afterall - I am not capping my FPS to 120, so isn't it basically pointless? I mean, we can see the Blur Reduction advanatge when the refresh rate equals the FPS (just like the UFO test), right?
When I first got the monitor, I capped the FPS to 120, but after many months I just went back to fps_max 300 (in CS), as I didn't really feel it made any difference..

What is your take on everything I mentioned? These questions have bothered me for quite some time.

Laslty - I keep reading around, and by the looks of it, you deem the V4 firmware very upgrade-worthy (over the V2), so I'm very curious and want to upgrade my firmware as well. Is there a way to do so without connecting the monitor to a Linux device or sending it to BenQ? D:

EDIT: You seem to be specific about the 2720Z and not the 2420Z. Will I get the same advantages with the 2420Z?

Thanks a lot!

[Falkentyne]

Thanks a lot for the in-depth explanation Falkentyne! I realize what that tweak is, or at least I understood the general idea behind it (as I mentioned, I've been using the 1350 one, and a brief explanation is also written there by the Chief). You provided some extra, so thanks for this. I'll probably give it another read again later!
I just couldn't understand how come the Chief wouldn't update it to 1502 (if it is obviously possible), but oh well! I changed mine to 1502 as well.
EDIT: Wow that guy posted this 1502 tweak back in April last year, a month before I got my monitor. So basically I have been using 1350 instead of 1502 for a whole year! But I'm assuming the difference isn't as noticeable from the original VT to 1350, right?

If you don't mind explaining something else to me... Why is it not recommended to use Blur Reduction along with 144Hz? Why are these tweaks only compatible with 120Hz? Is it because 144hz some kind of an upgrade and not really a refresh rate by jumps of 5? ._.

I play CS:GO (Counter Strike: Global Offensive), and literally every one around me (in case they possess a 144Hz BenQ monitor) use 144Hz and not 120 + Blur Reduction. I am literally the only one, and I've been wondering if I should just switch to 144Hz as well, because afterall - I am not capping my FPS to 120, so isn't it basically pointless? I mean, we can see the Blur Reduction advanatge when the refresh rate equals the FPS (just like the UFO test), right?
When I first got the monitor, I capped the FPS to 120, but after many months I just went back to fps_max 300 (in CS), as I didn't really feel it made any difference..

What is your take on everything I mentioned? These questions have bothered me for quite some time.

Laslty - I keep reading around, and by the looks of it, you deem the V4 firmware very upgrade-worthy (over the V2), so I'm very curious and want to upgrade my firmware as well. Is there a way to do so without connecting the monitor to a Linux device or sending it to BenQ? D:

EDIT: You seem to be specific about the 2720Z and not the 2420Z. Will I get the same advantages with the 2420Z?

Thanks a lot!

The difference from 1125 to 1350 is larger than the difference between 1350 to 1502, because the increase in lines is larger. But it's still noticeable.

And what I said applies to all of the Z monitors. Just the 27" monitor sometimes needs VT 1500 or VT 1498 while the 24" will work with VT 1500 or VT 1502 at the same resolutions. (example 85hz VT 1502 works on XL2411Z, but stutters/pulses on XL2720Z. VT 1498 works instead).

The main reason VT 1350 was posted instead of 1500/1502 is because the absolute limits weren't known at the time, and is less universal. 1500/1502 won't work at all refresh rates (may cause intermittent black screens or pulsating) while VT 1350 works at everything except 60hz (60hz is limited to 1260, or 1360 if you use bizarre timings).

50hz strobing is broken. While it double strobes at 100hz, the single strobe pulse widths are missing, causing strobe to not work at all (and the backlight voltage gets overdriven and the monitor may reset/turn off). If a VT is used at 50hz, it will strobe but will strobe at 60hz instead of 50hz, causing an unsmooth image.

Updating to V4 is easy.

http://forums.blurbusters.com/viewtopic ... &start=200

it affects all the Z series btw. improves quite a bit.

[masterotaku]

50hz strobing is broken. While it double strobes at 100hz, the single strobe pulse widths are missing, causing strobe to not work at all (and the backlight voltage gets overdriven and the monitor may reset/turn off). If a VT is used at 50hz, it will strobe but will strobe at 60hz instead of 50hz, causing an unsmooth image.

Note: in the XL2720Z.

In my XL2411Z, strobing at 50Hz with VT1360 (1502VT starts working from 51Hz onwards, with some exceptions like 60Hz) works fine, but strobe phase must be at 018 or higher. At lower values, the image looks doubled in movement. It isn't double strobing because the flickering is still massive, but the effects to the image are very similar.

[TwentyFoe]

Thank you Falkentyne! But I was asking whether or not the V4 changes will be as good for 24", because in that thread you were talking about 27" and were hesitant about the 24", but are you saying I can actually flash it using Windows? That's awesome, then! Saves me a lot of troubles, glad to hear it ^___^
I'll just flash it. the (probably tomorrow).

Anyways, bummer to realize (after a year) that I could have used a higher VT value, but oh well. I guess better late than never.

I'd still appreciate if you guys explained about the entire 144Hz + Blur Reduction thing. Why isn't it recommended to use?
And also concerning CS:GO:

If you don't mind explaining something else to me... Why is it not recommended to use Blur Reduction along with 144Hz? Why are these tweaks only compatible with 120Hz? I think the Chief once answered such question, but I can't find it now.

I play CS:GO (Counter Strike: Global Offensive), and literally every one around me (in case they possess a 144Hz BenQ monitor) use 144Hz and not 120 + Blur Reduction. I am literally the only one, and I've been wondering if I should just switch to 144Hz as well, because afterall - I am not capping my FPS to 120, so isn't it basically pointless? I mean, we can see the Blur Reduction advanatge when the refresh rate equals the FPS (just like the UFO test), right?
When I first got the monitor, I capped the FPS to 120, but after many months I just went back to fps_max 300 (in CS), as I didn't really feel it made any difference..

What is your take on everything I mentioned? These questions have bothered me for quite some time.

Thanks!

[Falkentyne]

50hz strobing is broken. While it double strobes at 100hz, the single strobe pulse widths are missing, causing strobe to not work at all (and the backlight voltage gets overdriven and the monitor may reset/turn off). If a VT is used at 50hz, it will strobe but will strobe at 60hz instead of 50hz, causing an unsmooth image.

Note: in the XL2720Z.

In my XL2411Z, strobing at 50Hz with VT1360 (1502VT starts working from 51Hz onwards, with some exceptions like 60Hz) works fine, but strobe phase must be at 018 or higher. At lower values, the image looks doubled in movement. It isn't double strobing because the flickering is still massive, but the effects to the image are very similar.

Nice find.
Just confirmed that at 18 strobe phase, it actually starts strobing properly at 50hz at 1360 VT on my XL2720Z.
So both 2411Z and 2720Z is the same.
But still the warning has to stand: if NOT using a VT tweak at 50hz, do not attempt single strobe. The backlight could possibly be damaged. A few games will force 50hz for no reason at Native resolution (Crysis, etc), so for that reason, I sometimes keep single strobe off (especially since V4 fixed strobe adjustments with SS off at 100hz+).

(this seems to happen at strobe duty 008-010 at 100% brightness. Trying 50hz without a VT tweak and single strobe will reset the monitor after a massive increase in brightness). Strobe duty 006 doesn't reset it (at least not right away) but I remember it resetting it after about 15 seconds back on V2. The brightness increase is beyond massive. it looks brighter than MBR on at 125 hz refresh rate with VT 1498 and *strobe duty 030!*. (just for reference, 125hz + duty 030 is brighter than blur reduction OFF and 100 brightness).

Unfortunately I now have a headache from looking at the flicking 50hz screen while typing this
Back to 100hz I go !

*edit again*.
STILL TYPING at 50hz because this flickering has me hypnotized.

1) no, you can NOT flash in windows. The only way to flash in windows is to use the Mstar ISP unit. What I wrote in the guide is, you may need to install the Z series INF driver in windows, IF flashing through DVI, for Ubuntu to see it (EVEN if you're booting from the flash drive). I do NOT know why. But another poster in the Linux thread said he could not find the monitor with i2c commands, until he went into windows, installed the driver, then went back into Ubuntu. he then saw the XL2411Z identifier instead of "unknown" random code at the proper i2c address.

2) People use 144 hz without blur reduction because it has the absolute lowest input lag. And CS:Go is not a twitch game, like Quake, so you can get by at 144 hz without blur reduction. And I'm guessing the reason they keep blur reduction off is because you can't use a VT tweak at 144 hz; Crosstalk (at the bottom of the screen) is too high without a VT tweak. I don't even game at 144 hz because of that reason (UNLESS I turn off MBR). I use 120hz.

3) try 125 hz with a VT 1500 tweak. If it stutters or the backlight pulsates, use 1498. I have to use 1498 on my 2720Z.

4) Masterotaku already mentioned that V4 improves XL2420Z and XL2411Z also. Default (non toggled AMA high) with motion blur reduction is only slightly improved. XL2720Z has bigger improvements (Probably because on V2, the 27" panel ALREADY had worse ghosting than the 24" anyway). The toggle (Turning on AMA high after enabling MBR, on V4) is improved on the 2420Z/2411Z, of course. it looks better at all refresh rates, but masterotaku said the biggest improvement is at 60hz and lower refresh rates. It's not as big at 100/120hz, but still worth updating anyway.

The toggle on xl2720z is different than yours. The toggle on xl2720Z turns the inverse ghosting into normal ghosting. The added normal ghosting can then be removed by contrast 0-10 (otherwise the toggle on 2720Z actually makes things worse at 43 contrast); with contrast 0 its better.

[whitestar]

Honestly I don't see much difference between 1350 and 1500, so I have just gone with 1350 lately. That way I don't have to hack the drivers.