240hz freesync monitor going white screen now using an amd card - Acer XF270H

DazFx81

Basically, I have a 240hz Acer XF270H A which is free sync, using an Nvidia 1080 ti I could select 60hz, 120hz,144hz and also  240hz they would all work no problem.
Switched to an RX 6800 XT and done the usual, DDU the Nvidia drivers etc then install Radeon software.
However, when I know to switch to 240hz mode the screen goes white after 10 seconds, I have to turn it off, then back on, then quickly switch to 144hz mode then it's fine.
The screen works in 60hz, 120hz or 144hz with the RX 6800 XT but not 240hz mode even though the screen is free sync and the graphics card is free sync.
The only time the screen did the same thing (went completely white) on my Nvidia 1080 ti is when I accidentally activated Gsync on the 240hz freesync monitor.
It seems as though AMD Radeon software is doing something weird with 240hz mode.
I thought maybe it is something to do with skipping frames etc, so I tried to set a custom resolution in Radeon but there are loads of options in there unnecessary.
If you don't put the correct values in, it will not let you set it, at least with the Nvidia control panel you select the resolution and the Hz etc, easy peezy.
Radeon is asking for g.pixel clock, g.refresh rate, timing front porch and timing sync width, when you change to 240hz those other values should change automatically but they don't.
I'm at my wit's end and really am starting to hate AMD and the problems I have had with their tech over the years.
Maybe I am overlooking something or am simply being plain stupid in my frustration.

//Edited the content to add model name.

DazFx81

Solved, My Acer XF270H A only has a free sync range between 60hz-144hz.
As soon as I disabled free sync on the monitor and also in Radeon software the monitor now runs as 240hz.
Pretty strange the monitor does not free sync up to its full range but at least I have solved it.