Long loading time in Linux Mint

I am using Linux Mint 15 (x64) and everytime I start Gmod, it gets stuck on the blue “Loading…” screen for more than 90 seconds before continuing and finally loading the menu (it only takes about 2 seconds on Windows, same harddrive). Any idea what could be the problem or how to try to debug this?

EDIT: Also tried on clean install of Ubuntu 13.04 (x64), same thing.

EDIT2: I reinstalled Mint few times and now the problem went away and it loads in just a couple seconds…weird.