It has been said by some that since there is no dedicated server version of the game(running a server as you would host the game from your home PC) that it is not optimized and is causing server side lagging.

But it would also help I believe if when people report their issues the do a search and add their info and notes to already open tickets so the devs have fewer to respond to. Not trying to flame OP here just saying if 50 players have the same issue they do not each need to make a ticket they just need to add to ones already open. The less they have to comb through the quicker we will get results.

Just saying

I use trackIR and it works smooth, have you adjusted your profile in the trackIR software? If you haven't try to adjust the graph points so the movement is more spread out.

Just trying to help

Edit: Sorry I missed the part where you said you checked it