Samsung 57" Neo G9 possible to run at 3840x1080 HiDPI @ 240Hz via DP 2.1 on M4 Pro/Max

[murphis123]

Hi all I was super excited about the potential for my M4 Pro to drive my Samsung at full spec in HiDPI mode @ 240 Hz, but so far I haven't been able to exceed what my M1 Max could do via CableMatters USB-C to HDMI 2.1 cable (3840x1080 HiDPI @ 120Hz). I've tried looking for ways to enable a custom mode at that refresh rate but haven't found a way to do so yet. If will do the target resolution I figure frame buffer isn't the problem, but something is preventing a 240Hz config. I can only get 240 Hz at 3840x1080 without HiDPI.

[murphis123]

FWIW this is the cable I'm running https://www.amazon.com/dp/B0D82WY6FK?ref=fed_asin_title&th=1 and the Samsung monitor is set to DisplayPort 2.1 in 240Hz mode.

[Neversettle1492]

Tried this exact same thing today just got my g9 57in in and had m4 pro mac mini a week now. I used a cable matters usbc 80gbs to DP2.1 cable adapter and reached the same results best I could get was 3840x1080 at 120hz with hiDPI or same with 240hz with no hiDPI coming straight from thunderbolt 5 to an 80GBs to DP2.1 adapter. Tried using better display to tweak the resolutions to get any custom resolution below or above 3840x1080 with hiDPI and would couldn’t het any to get hiDPI with 240hz rather monitor was on 240 or 120 in its settings or freesync was on or if I put display options in variable or always 120hz. I did find in variable refresh mode had some flickers when opening finder and moving mouse around though. So for now I’m stuck at 120hz non variable at 3840x1080 hiDPI. with adapter and cable rated for 80GBs and DP2.1

[Neversettle1492]

https://a.co/d/958J1iC

I am using this adapter with included DP2.1 cable with monitor set to DP2.1 and at 240hz and had to switch back to 120hz on monitor to get outta 60hz with that resolution even

[murphis123]

Misery loves company. Perhaps the M4 Max will be able to do this?

[Neversettle1492]

Maybe but I doubt it. I also have the Kensington thunderbolt 5 dock that is capable of three 4k displays at 144hz and before getting the G9 I had 3 MSI 4k 240hz OLEDs and could only get one at 240 via HDMI and 2 at 60hz on thunderbolt with or without dock. Or using only 2 of the displays could only get one at 240 and one at 120 Then again the best card from Nvidia can't pull it off until they upgrade to DP 2.1