I've been using an ASUS 144hz for a long time now, after a year of using one I decided to plug in my old monitor which is only 60hz so i could have 2 monitors. It has been working fine.
Recently I reformatted, I've already updated my graphics drivers, and I've gone into the screen resolution menu to set the asus to 144hz. On my desktop, it works fine and runs in 144hz as far as I can tell. When I launch tf2, it is very clearly not in 144hz. If I disable the second monitor and THEN turn on the 144hz, it works inside TF2, however when I reactivate the second monitor TF2 reverts to using 60hz.
Any help?
edit: this only started happening after reformatting.