At the time, I had it with i7 7700k, and it started at 100hz. For game settings... I mean office applications, switch to Full HD 144.

Well, I have the Samsung LC49RG90SSRXEN (49", 5120 x 1440 pixels), 120 Hz and use it for office purposes with a Surface and an i5-6300 CPU. Works normally/very well. However, I don't know at what frequency - I think around 60Hz.