irradic zoom behaviour on macpro, perfect on MacBook. drivers?

ook so I've been using lofuc professionaly for 10 years now, every day of the week. I've been here since the logic 7/ dongle days and been through 5 different computers. all have worked fine, untill logic x, it has some wierd acceleraction going on where one mousescroll "click" sometimes gets ignored, and there is always a long delay between the mouse action and the visible zoom same with scrolling... only logic x, and what I figurdd out only on my macpro5.1 with 2 3.33 xeons and the ati5770 ! I took a session ( running off a FireWire drive, plugged it into my MacBook pro 2012, same mouse, same hard drive, same session and zoom and scroll work perrrrfectly! no irradic jumping to the end of the session, no accidentally zooming alllllll the way out, no lag with zooming. I mean perfect! now what the **** gives? i spent a couple days formatting hard drives and doing clean installs of Mavericks and Yosemite on both computers and still, the issue follows the macpro! any advice? I'm seriously about to give up on logic for good... the program itself and it's quirks I can deal with but when every waking second of me working on a session I feel like my computer is grinding to a halt because of this lag. oh, and zero lag in logic 9 on both computers:( does it have something to do with the multi touch drivers? or what? theres got to be a fix! and no, usb overdrive doesnt fix the issue, just makes it slightly more tolerable.