Audition, being a piece of software, doesn't have drivers. However, there certainly should be alternative 64 bit drivers for you Presonus. That'd be my first stop--download the latest Win7 64 bit drivers from HERE.
The other thing I'd look at is to peek and see what extra bits you may have running in background. Computer manufacturers have a nast habit of adding all sorts of un-necessary rubbish to their installs, some of which can get in the way of audio work. When i get a new computer, my first hour or two is generally spent cleaning it out and getting rid of all the 'try this' rubbish.
Finally, the usual advice about turning off system sounds, anti virus, wifi, etc stands as does going through things on an "optimise your PC for audio" site. THIS ONE on the Focusrite site seems as good as any even if you don't have Focusrite hardware.
The pessimist sees the glass as half empty. The optimist sees it as half full. The realist just drains the darn thing and gets a refill!