Right so you need to make a custom res.
if u got nvidia CP then great sadly i know nothing about any other. click on customise then click Create Custom Resolution.













for me I like 1440x1080 although you may want something different. I changed HP and HZ as shown.
when you've created your res save change to the new res.













You may have black bars but just head over to the Adjust desktop size and position.
-Change Aspect Ratio to Full Screen
-Perform Scaling on Display
-Do not override the scaling mode
-use custom resolution instead of 1920x1080 in my case that will be 1440x1080
-then change Hz to 144.

Navigate to csgo and right click on the game and go to launch options,
There I've typed -freq 144
unsure if it does much but it's always been there anyway so.. cant hurt.

here's what i have as my launch options.
-novid -high -nojoy -tickrate 128 -d3d9ex -noaafonts -freq 144


for the screenshot im going to be using normal res and windowed mode you dont have too.










Your settings should be like this.
-Aspect Ratio=4:3
-Your custom res
-Fullscreen

ok so when i was messing arround i first tried to use 240 hz and when i did steam started to be buggy my mouse was visible but when i hover over certain icons on steam it would be highlighting the option above it.

what i done to fix this was open Task manager and force close steam, and then reopened it.

After that it started to work again..

FYI i discovered this issue with the same settings but with 240 hz instead and i happens when i apply the settings from my native res.

Instead of using 240hz i used 144hz and so far i havent found any issues.


if you got any problems please let me know, i'll try to help you.