Just got a couple of wierd freezes when running the latest GIT on Ubuntu 14.04, it hogs almost all CPU and sometimes it just freezes the whole window system and I had to reboot once as well. I have tried both a new driver and an old known good single driver build and both has worked like a charm up until now.
Mingw under Win-7 compiles and runs the same drivers nicely, however the load and start up time is about 30 seconds now which is like 3-5 times longer than before.
Both are 64bit and I just add the -debug and -window flags at the command lines. EDIT: Ubuntu is running on an ASUS K52J laptop, Intel Core i5 - 480M @ 2.88Ghz, 4Gb RAM and an AMD Radeon HD 6370M. Mingw runs on a newer DELL laptop with a Core i7 and same or better of the rest.