Question on Additional Improvement In Ghosting [for VT1350]

[cast]

does it really changes so much ? playing 120hZ withAdditional Improvement In Ghosting: “Vertical Total 1350″ ? instead of the 144 hz

[Chief Blur Buster]

does it really changes so much ? playing 120hZ withAdditional Improvement In Ghosting: “Vertical Total 1350″ ? instead of the 144 hz

Yes, it changes significantly, if you are sensitive to ghosting. Here is an illustrated diagram of the double-image ghosting artifact during strobing. The artifact becomes more intense at higher refresh rates. Now, to compare the before and after, see before photo versus after photo.

Why Is There Less Strobe Crosstalk/Ghosting At 120Hz than 144Hz?

There are two primary reasons why strobe crosstalk (double-image ghost effect during motion) become significantly reduced with 120Hz + VT1350 tweak:
1. At 120Hz, there's more times between refresh cycles to let LCD GtG pixel transitions finish, for strobe backlights.
2. At 120Hz, there's more dotclock headroom to create a longer pause between refreshes, which the Vertical Total tweak does.

The Vertical Total tweak (1350 or 1500 scanlines per 1080p refresh cycle) is essentially a larger blanking interval inserts a pause of (1350-1080)/1080th of 1/120th second between refresh cycles. That's about 2 milliseconds pause between refresh cycles, which is long enough to completely hide most of the real-world 1ms GtG pixel transitions between refresh cycles (in total darkness between backlight flashes). So the double-image ghost effect goes down very dramatically. Combined with careful calibration of the timing of the strobe, most of the ghosting ghosting occurs off the bottom edge of the screen (previous refresh cycle ghosting) and before the top edge of the screen (next refresh cycle ghosting). Adjusting "Crosstalk" in Blur Busters Strobe Utility changes the strobe timing, which moves the ghosting upwards/downwards/offscreen, and your goal is to adjust the ghosting so that it goes offscreen.

With the VT1350 tweak, you are essentially doing panel scanout faster (approximately 6.2 milliseconds per refresh cycle) in order to let the panel idle longer between refreshes to let renmant GtG to finish between refresh cycles (1/120sec = 8.3ms = so refreshing for only ~6.2ms means a ~2ms pause between refresh cycles). This luxury is not currently available at 144Hz yet due to LCD technology & electronics limitations at this time.

It has been long known that CRT 75fps@75Hz has less motion blur than non-strobed LCD 120fps@120Hz, so to make proper LCD strobing possible and relatively ghost-free, pixel transitions need to occur in total darkness between strobe backlight flashes (high speed video). This is the premise behind all the new motion-blur-reducing technologies, including LightBoost, ULMB, Turbo240, BENQ Blur Reduction, which are all low-persistence strobe backlight technologies that aims to achieve CRT motion clarity on an LCD panel.

You can view the TestUFO Alien Invasion Test with Height->"Full Screen", in a supported 120Hz web browser, to calibrate the ghosting with Strobe Utility.

TL;DR: Motion clarity is better at on most strobed LCD technologies at refresh rates (120Hz) lower than the monitor's maximum (144Hz), due to more time for LCD GtG (grey-to-grey) pixel transitions to finish in the dark between refresh cycles.