It's already optimally tuned. I personally tuned it. There are law-of-physics limits at higher Hz. The moment a ghost disappears, a corona appears. At some point, you can only tune so much, it's impossible to eliminate both because you're flashing two different GtG's simultaneously.
But the crosstalk is faint enough at 120 Hz. Remember that the crosstalk is highest at the top/bottom edge instead of center. If you drag www.testufo.com/photo lower on your screen, the Quebec City skyline buildings go crosstalk-free ... That's because of the GtG-time asymmetry between the sequential LCD scanout and the global backlight flash. Each pixel are at different stages of their GtG curve when the screen is globally flashed. If you see the high speed videos you will understand better.
Most manufacturers are generally reluctant to let users adjust overdrive in strobe modes due to custom overdrive needed.
Fortunately, the OD is pretuned to the lowest possible crosstalk at a pre-calibrated LCD temperature of 20 degrees C.
It is preconfigured to a custom overdrive setting that is different from the OD presets.
A minor compensation adjustment is useful especially for temperature compensation because a different overdrive gain is required for a cold room (15C) versus a hot room (25C), as LCDs tend to react slower at lower temperatures, causing ghosting/corona differences. This may be the premise that wins. I'll suggest it to ViewSonic.
Alas, that's the rock and the hard place in strobe backlight engineering.
It affects all monitors -- Hertzroom is your friend -- Choose a lower Hz than max when you enable strobing and want CRT clarity. Some manufacturers (NVIDIA) lock you out of high-Hz strobing due to poor quality. But at least ViewSonic lets you choose a higher Hz if you wish.
I've publicly written about this since 2013 in various places on Blur Busters.
Cramming GtG into the VBI. Usually you have only a ghost and a corona, but you can get both when the rock and the hard place is getting closer (ever shorter and shorter VBI, with constant-time GtG colliding against shorter-and-shorter refresh cycles). At that point, you're strobing the end-top GtG curve of the previous GtG and the beginning-tip GtG curve of the next GtG transition. No possible OD setting can eliminate both coronas or ghosting simultaneously. All strobed monitors are exposed to an amplified crosstalk phenomenon as strobing reaches max Hz. The refreshtime:GtGtime very difficult law-of-physics situation that can only be solved by ever faster pixel transitions GtG that more easily squeezes between refresh cycles.
Also, if you don't mind a little crosstalk, and want to test even lower-latency strobing -- try testing 180 Hz and 230 Hz. Use a Custom Resolution Utility. Those look noticeably better than 240 Hz, there's a sudden improvement the moment you go down to 230Hz. There's a strong geometric behavior to strobe crosstalk reductions the lower you go from 240 Hz.
Hertzroom is your best friend for crosstalk-free strobing. This is true for all past, current and future strobed LCD monitors. One will probably a 360Hz-480Hz monitor (or something like a 1/360sec or 1/480sec scanout, with long enough VBI between scanouts) to get lower crosstalk at 240 Hz. Does not matter which vendor, strobing at higher Hz will have more crosstalk limitations until GtG gets faster and/or the scanouts gets faster (creating longer VBI -- longer pauses between refresh cycle scanouts).
Some stuff I've written since 2014:
- Pixel Response FAQ: GtG versus MPRT (educational)
- High Speed Videos of LCD Scanout (videos showing GtG in realtime)
- Electronics Hacking: Creating A Strobe Backlight (complex piece)
Thanks for the compliment!
It is truly the best strobing I've seen on any three-figure-priced monitor in color-quality combined with crosstalk-free (at low Hz).