BenQ XL2411Z/XL2420Z LCD panels and PCBs

[MicroMouse]

According to this:

http://display-corner.epfl.ch/index.php/BenQ_XL2411Z

upgrading to Z firmware on the T series cannot be done.

Too bad, because I also have the XL2411T.

The LED driver wiring is different.

[Chief Blur Buster]

According to this:

http://display-corner.epfl.ch/index.php/BenQ_XL2411Z

upgrading to Z firmware on the T series cannot be done.

Too bad, because I also have the XL2411T.

The LED driver wiring is different.

Thanks for pointing this out! Yes, StrobeMaster's page definitely would confirm it's no go for attempting to flash XL2411Z firmware on XL2411T. The original XL2411T isn't PWM-free, while the XL2411Z is.

[Bishi]

Noooes

Ah well, thanks for stopping me before I bricked it I suppose

[Falkentyne]

According to this:

http://display-corner.epfl.ch/index.php/BenQ_XL2411Z

upgrading to Z firmware on the T series cannot be done.

Too bad, because I also have the XL2411T.

The LED driver wiring is different.

Thanks for pointing this out! Yes, StrobeMaster's page definitely would confirm it's no go for attempting to flash XL2411Z firmware on XL2411T. The original XL2411T isn't PWM-free, while the XL2411Z is.

Chief
Strobemaster's page also goes very in depth as to how lightboost and blur reduction differ and why blur reduction has those crosstalk artifacts that lightboost mostly eliminates (per line overdrive, or something he said), and some other nice details.
He also said that setting contrast to 40 (instead of 50) gives bests overall results for blur reduction.

[Chief Blur Buster]

[Warning: Technical reply below!]

Chief
Strobemaster's page also goes very in depth as to how lightboost and blur reduction differ and why blur reduction has those crosstalk artifacts that lightboost mostly eliminates (per line overdrive, or something he said), and some other nice details.

Yes, that's what I call Y-axis compensated response time acceleration in Electronics Hacking: Creating A Strobe Backlight, but it can also be called "per-line overdrive".

One additional observation, that I would like to add -- color quality of a monitor is dependant on its scanout speed, so 60Hz has better color quality than 120Hz, which has better quality than 144Hz, which has better quality than LightBoost (which scans out even faster). That said, LightBoost produces somewhat lower contrast ratio (poorer color quality) since its scanout is even faster than in BENQ Blur Reduction mode. The Vertical Total tweaks do accelerate scanout, but not nearly as much as LightBoost does.

Colorimetric observations (i1 DisplayPro) shows a continuous degradation of Contrast as you increase scanout speed (increases refresh rate; or increase vertical total, or LightBoost accelerated scanout), probably defined as less time to send voltage into each pixel. LightBoost is always forced to have fast-scanout, and thus have to have the extra contrast degradation, down to as low as 500:1 to 600:1 contrast ratio for a 24" strobed panel, whereas BENQ Blur Reduction can maintain close to 1000:1 contrast ratio. (Beyond this, there's also the LightBoost built-in gamma bump, and often, color tinting, that can't be undone via monitor adjustments, but can be undone via GPU LUT adjustments)

He also said that setting contrast to 40 (instead of 50) gives bests overall results for blur reduction.

That's right, if you're aiming for reduced strobe crosstalk. If you're wanting punchier colors at the tradeoff of a little extra strobe crosstalk, raising contrast to 50 is very desirable. Contrast 40 looks better at http://www.testufo.com/ghosting (less artifacts) and for vision research that makes sense. However, often Contrast 50 can look better in real-world gaming, depending on what your goals are (Less strobe crosstalk? Better colors? Etc.)

When both LightBoost and BENQ Blur Reduction are adjusted equally to achieve maximum contrast at http://www.lagom.nl/lcd-test/contrast.php without color clipping -- When you adjust both LB versus BENQ BR, it is observed that BENQ Blur Reduction still has better color than LightBoost, with deeper blacks (higher contrast ratios revealed by colorimeter), especially on the 24" model (XL2411Z / XL2420Z) which suffers greater contrast-ratio degradation during fast scanout than on the 27" models (I have several 24" and 27" strobed monitors and it's interesting that contrast ratio degrades more dramatically in strobe mode only on the 24" models). And the ability to go to lower refresh rates improves colors even further too.

The only thing from a gamer's perspective is that I feel LightBoost is superior, is the reduced strobe crosstalk, but it is really not worth the degraded colors that LightBoost provides (often non-adjustable via monitor controls), where BENQ Blur Reduction lets you adjust the picture fully via monitor picture adjustment controls, with a much more flexible refresh rate range, and far better colors. The Blur Busters Strobe Utility (V2) allows crosstalk to be pushed down to very manageable levels, without needing anything more than a slight scanout speedup from VT1350, rather than the larger scanout speedup that LightBoost uses for even larger pauses between refresh cycles (which helps greater reduction in strobe crosstalk, in addition to the scanline-optimized RTC / Y-axis-optimized RTC). The VT tweaks and the LightBoost scanout speed up behavior is the same kind of LCD panel refresh scanout speedup, but LightBoost actually pushes the scanout faster (similiar to ~1/200sec scanout) which is faster than doing it via an external dotclock (doing large blanking intervals on the cable).

StrobeMaster's findings is very accurate when focussed on motion blur reduction quality / strobe crosstalk, which is the prime focus of his findings. Currently, it does not cover the contrast ratio degradation differences of LightBoost (greater contrast ratio degradation) versus BENQ Blur Reduction (less contrast ratio degradation).

He has done an exellent job, it took a lot of work to research the monitor's motion blur / crosstalk behaviors this closely!

[Disgusted]

Greetings,

Can anybody compare colors of the BenQ XL2420Z/XL2411Z to the Samsung T220?

[Chief Blur Buster]

Can anybody compare colors of the BenQ XL2420Z/XL2411Z to the Samsung T220?

The T220 is a TN LCD panel, so for a calibrated Z-series running at 60Hz versus the T220, would likely have extremely similar colors.

Running at a higher refresh rate, will likely slightly degrade colors, but not everyone notices the color degradation. The BENQ factory adjustments may not be ideal, so the picture will become much better looking when you load the XL2720Z .icc file.

[jossesphere]

[Warning: Technical reply below!]
[...]

That was some epic knowledge being poured on one post. After much research I got myself an Asus MG248Q, and I'm not too happy about how LB has to be managed, no color configurability on monitor and having to set it up everyday is a hassle. I'm seriously thinking about sending it back and grabbing myself a BenQ XL2411Z, to make my life easier and also have the option to go up to 144Hz with MBR.

Many thanks for all the info shared on the topic, making life easier for the rest of us!