I've had this problem for a while, Google Chrome seems to lower the FPS of WebGL content / games to 60 FPS on a dual monitor setup, even if my main monitor uses 144Hz !
Well, here is what I think is happening: chrome seems to use the first monitor as a reference to determine the desired FPS of WebGL contents. Now, that does not mean the "primary display" setting, I am talking about the actual numbers you can see in
Settings > Screen Display, those numbers :
They are assigned by the actual firmware, and so far the only way I've found to change them is to swap display cables on the back of my GPU !
So basically, if your dual monitor setup contains a monitor that is 60Hz, make sure it's not the monitor with number
1 assigned, swap cables until your best monitor is
1, then the problem should be fixed !