I noticed that Civ BTS doesn't freezes whenever I've closed FireFox and Gtalk and removed a sata drive.
With those 3 items in place the game freezes in random places in any game I play.
The bad thing about that freeze is that I've to reboot and restore my pc to a previous state (otherwise I can't get my internet back) and that it freezes ofcourse ;)

In my current game it has happen twice, I'll restart and remove the SATA HD to confirm my suspicions (it's an movable one)

Edit : ... and it doesn't freeze no more ... after removing it
I installed Civ on another sata drive (in case it matters).