TLDR; If you're playing CSGO, Valorant, or any other competitive FPS, I think you will be better off without PureXP. I settled on PureXP off, OD Fastest G-Sync ON, Refresh Rate 224hz, FPS Limiter at 220.
The OD is one of the best I've seen on this monitor, even at 224hz. Compared to my Asus PG348Q at least, which creates overshoots everywhere on Extreme.
Why the above settings? The reason being is that even with CSGO with my setup (Ryzen 3700X & 2080 Super), it's very hard to have constant 224fps/224hz for PureXP to look it's best - CSGO tends to dip to 180 in some areas and back at 220. Valorant goes from 160-220 a lot.
The latency between G-Sync (with FPS Limiter) and V-Sync Off is almost negligible (1-2ms at best, which is really low. You can read all
about it here of course).
Initially I wanted to really make PureXP work even for competitive games (despite the input lag, which I did not perceive at all - primary reason I leaned towards this monitor was at how much PureXP was praised). I found PureXP Extreme @224hz to be a good balance between Brightness and Performance. Though, as explained already in a number of other posts, it looks glass smooth if you can constantly match FPS/Refresh Rate, and at such high frame rates - it's very hard to hold the constant high fps. I did play with this setting initially (PureXP On Extreme, G-Sync Off, V-Sync Off, FPS Uncapped) and actually, I found the whole thing to be quite pleasing and, albeit not perfect. I think strobed + uncapped fps + 224hz + vsync-off is something a lot of people can and will be playing with (even on other similar monitors).
So then, I decided to tone down to 144hz/144FPS which is more achievable for Valorant (V-Sync Off though, cause latency competitiveness). Unfortunately the experience wasn't as glass-smooth even with the more constant fps/hertz as I hoped and I played a whole match with a lot of micro-stuttering that was annoying, something I never noticed with other settings. Could be an engine thing, though most probably V-Sync On would've helped here. I didn't bother testing that one out.
And then, I switched PureXP off, set-up OD to Fastest, tried V-Sync Off and G-Sync ON with FPS Limiter, and I just fell in love. It honestly looks almost as good to PureXP at 200+hz (even doing the UFO Blur Test), you get no tearing thanks to G-Sync, you can have your frames stay within maximum hertz without having the need to have your computer hardware screaming for maximum unbounds frames as possible.
So in a nutshell, I think you get more benefits if you cannot keep your frames constant, and at 200+ FPS, you're most likely to be CPU bound in a lot of these competitive games, and the game would probably look best with G-Sync On.
So, no more PureXP? Well, no actually. I think for your desktop, 120hz + V-Sync On looks really really really good. The CRT effect is there, the UFO looks amazing, and I will most probably play 120hz with PureXP Extreme + V-Sync ON for a number of games, like Warcraft III, Warhammer 2, Forza Horizon. Call of Duty Warzone for example (a less competitive game), 120hz+PureXP Extreme and V-Sync just looks so clean and smooth, it's very hard to explain other than use the term "glass smooth".
But for CS, Valorant, I'm going for G-Sync with FPS Limiter and rely on OverDrive instead.
Conclusion This is the best looking monitor when it comes to motion and colours (if you're OK with 1080p at 27" - I think it's fine whilst gaming at the right distance, plus you get extra frames!) - I am incredibly happy that IPS panels are giving TN panels a run for their money in terms of performance. I just cannot stand TN panels even for CSGO. I swore that after I sold my older AOC G2770PF I would not get another TN panel - it just looks really pale especially if you have another decent monitor paired in your desk.
My criteria for buying a new monitor was: Primary aim was for competitive FPS games (CSGO,Valorant), and decided to go to 240hz instead of 144hz regardless of diminishing returns for an upgrade as higher frames, means lower input lag. After having a massive list of monitors, it ultimately all boiled down to the Asus VG279QM (or I was very close on getting the 144hz+ 1440p Asus VG27AQ as well.) and the ViewSonic XG270. What made me get the XG270 was the fact how PureXP was highly praised, and that I raid that even though Asus can do Adaptive Sync + ELMB (ELMB-Sync), it just wasn't as good as PureXP, though I am very curious to test out such a panel.
