Weird fps\mouse lockups on goldrush

I think it's only on sw_gold, it may happen on other maps, sometimes oasis_b3, but mostly gold.

Every minute or so, at random I get fps lag, the game just freezes for a second and I can't move my mouse, it only started happening a few days ago.

I got a new mx518 a week ago, and it worked fine at first but could this be the reason?

Solutions anyone?