HDMI may be only 30 or 60. Since there are so many old 750s out there I can't guess if yours has DISPLAYPORT which would be the choice for other than the usual standard 50 and 60Hz display connections.
In short I'm an osu player and was looking to upgrade to 144hz monitor with 1ms response time. I usually have 480 FPS in osu with this graphics card (gtx 750) however i just wanna make sure I don't waste my money for no improvement. I don't know much about monitors but i heard that not all connections support 144hz so I was wondering if it would work.
And if this gpu is not compatible what upgrade would you recommend (12gb of ram, fx 6300, gtx 750, some random black list 500w PSU)