Wait, you bought the XL2720Z? Yes that's V4
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P.S Set strobe phase to 000. 100 has too much crosstalk at the bottom of the screen and is incompatible with vertical total tweaks (VT tweaks on PC are HIGHLY recommended to lower the strobe crosstalk); the backlight will turn off in blur reduction mode, if the strobe phase is higher than 059 at 100hz refresh rate (with a VT 1500 tweak) or if higher than 049 (120hz with VT 1500 tweak). 100 isn't bad if you have a gigantic game HUD covering the bottom of the screen, though, on a console.
The XL2730Z doesn't have those settings (strobe duty and strobe phase have been renamed to "intensity" and "area" and have been moved into the OSD itself), and Single Strobe setting was omitted...might have been forgotten to have been added into it. We're hoping a firmware update for the XL2730Z will add single strobe option back.
Anyway, for your new screen, yes, Single Strobe needs to be turned on for 60 hz console gaming. That's one of the reasons that option was added.
Note: if ANY of your devices use 50hz, turn OFF single strobe. There is no strobe information available for 50hz refresh rate (double strobe uses 100hz strobing which is basically strobing twice at 50hz), so attempting to enable single strobe at 50hz simply increases the current to the backlight beyond its limits and it doesn't strobe (overcurrent protection may make the monitor turn off or reset).
The monitor was originally designed to "double" strobe (back in V1 firmware) from 50-90 hz, and single strobe at 100-144 hz, without custom strobe adjustments. This was inflexible and made it even worse than the Eizo FG2421
The single strobe option was added in V2 to allow 60hz-144 hz single strobing and to allow custom strobe duty/phase adjustments. But there was never any 50hz strobe pulse data added.
I only mention this because I know this is a UK forum and there's something about PAL and 50hz in the UK, while the USA uses NTSC and 60hz.
Yes you have V4 firmware, which means you also have a new (hidden) overdrive setting (Blur reduction+AMA high) which if toggled after blur reduction is enabled first, changes the AMA calibration and removes the inverse overdrive ghosting (the default on V4 has minor inverse ghosting, but is otherwise very nice). Then by lowering the contrast down to 0-10 after trying this toggle (required or you will get too much normal ghosting), you get an even nicer overdrive curve, at the expense of contrast. It's a very nice setting for high contrast 2D side scrolling games.