Xbox Series X cannot run at 120Hz with an old HDMI 1.4 monitor

for 120hz you need i think hdmi2.1.

besides connecting the s at 120hz is not going to magically let it run at 120fps, you will be lucky to get 40fps on most games. kills my eyes running so slow.

HDMI 2.1 is only needed if you plan to game at 4K for 120hz , on a 4K 144hz monitor, However there's no gaming monitors available at the moment, that yet has HDMI 2.1, the first HDMI 2.1 monitors that are likely to come in are around the same time as the
Series X (Q4) launch or early 2021 (Q1),

1080p and some 1440p monitors can do 120hz over HDMI 1.4 if it's supported, but best ideally is HDMI 2.0 for 1440p for 120hz,

HDMI 2.0 can do 1080p / 1440p at 120hz and 4K at 60hz,

HDMI 2.1 can do 1080p / 1440p / 4K at 120hz.

For the Xbox Series X, it best to get a 4K TV or monitor that supports 120hz and has HDMI 2.1, to get the full potential out of the Series X.

It's nothing to do with your console...it is a limitation with your monitor.

Your monitor comes with 2 HDMI 1.4 ports (not 2.0)....120Hz and 144Hz are only supported via DP on this monitor, so this would be why it is defaulting back to 60Hz every time

Here's a forum thread on Linus Tech Tips about it (albeit with the better Series X but it's the same thing):

https://linustechtips.com/topic/1286444-monitor-cant-run-xbox-series-x-at-144hz/

Edit: Have edited the thread to provide more clarity regarding HDMI 1.4

Hello Mega! I'm Claus, an Independent Microsoft Community Consultant for Xbox! Glad to be able to help you!

Given that your monitor only has HDMI 1.4 and DisplayPort, and also given that the Xbox Series X only has an HDMI output, your monitor wouldn't support 1440p at 144Hz. HDMI 1.4 only supports up to 1080p/120Hz or 4K/24Hz.

my sons 1080p msi 27" monitor supports freesync and 144hz over hdmi, it also supports 120hz for ps5 and xbox series consoles too. this has hdmi 1.4. Also tested.

Without display 1.4 support there is no reason to target 1440p at 120hz. Only screens are able to do this have 4k 120hz with HDMI2.1.

Hi,

Sorry you feel this way, but that is not true. There are compatibility issues with monitors and the Series X/S sure, but there are some monitors that can do 1440P 120Hz via HDMI 2.0 without issues.

The Five listed here from Rtings.com can all support 120Hz @ 1440P over HDMI 2.0.

I have also seen on here that the Samsung G7 can also do 1440P @120Hz effortlessly.

Just because your monitor doesn't work doesn't Microsoft were lying.

Also there is a lot more to the Series X than just a fast SSD. It has a GPU at least twice as fast as the Xbox One X and a CPU 3x faster. The Series X also has Raytracing.