i have already report the gsync issue to nvidia support team, we need to wait the team to fix this issue, if you want to use 240hz with g-sync, you can change it to 3840x1080@240hz in the game, or use 5120x1440@240hz with fast sync.
I just tested with the same version of driver on my 3080, and despite everything, impossible to put me in 240Hz, even in SDR. It gives me a black screen. A screen at 1500 euros and a graphics card at 1000 euros, the bug is expensive anyway.
Same here. 3080 can get to 240hz with g9 and Gsync enabled. I'm even getting flickering at 120hz. This is my second g9. I'm going to have to go with the LG. This monitor is too buggy and not reliable
I just swapped to the cable that came with the odyssey and it seemed to help with the flickering with Gsync, adaptive sync, at 120hz. 240hz is still impossible. tried without adaptive sync and without gsync to no avail.
I am having the same issue. I hope a new Nvidia driver fixes it soon as it is quite annoying when a game forces HDR (like Sekiro does) and I have to reduce my monitors refresh rate.
Well I'm relieved to hear others are having the same issue, but then again I"m not... I just spent the last 2 days troubleshooting a brand new G9. I tried updating the firmware, graphics cards, windows, swapping cables and computers and I had no luck booting up any games in 240hz (Fortnite, Shadow of the TR, Fallguys). I tried a brand new PC with a 2080 Ti and every game would glitch out on startup and either blank out the screen, crash my PC or startup in some crazy resolution or tiny window . So I tried my other brand new PC with a 3080 and it will not display anything at all when the monitor is set to 240hz (annoying as  for over $8k) in equipment! Samsung what the heck is your problem?! I contacted samsung twice and got the run around asking me to send the monitor in to be physically inspected. Why the heck would I send in a 1000 pound monitor back to you guys, knowing its more than likely software\firmware that needs to be resolved?.. I setup a replacement with Newegg because I was afraid I have a defective panel. (It wack these panels are not eligible for return!) Im afraid I will go through all the  to have the same issue, if not worse with a truly defective monitor on the second try.... Does anybody have anymore info on this issue? Obviously samsung customer care is just going through the riduculous motions, and the reps dont have any answers when contacting them. Im afraid to go through all the trouble of replacement and end up with a truly defective monitor, or send this brand new monitor back to samsung, so it can tumble around in shipment twice just to get it back in a worse molested state. .... sorry i have issues....
if anyone has any info on this, please share. Thanks 🙏
Boys and girls...after losing a full day over this and almost returning the monitor...I found a post somewhere that fixed my issue.
Nvidia released two days ago a hot fix for this specific issue.
Just install the 456.98 Hotfix and bam..240hz
Hope this helps!