I love git and use it on OS X pretty much constantly at home. At work, we use svn on Windows, but want to migrate to git as soon as the tools have fully matured (not just TortoiseGit, but also something akin the really nice Visual Studio integration provided by VisualSVN). But I digress...
I recently installed msysgit on my Windows 7 machine, and when using the included version of bash, it is horrendously slow. And not just the git operations;
Run as administrator
The solution for slowness on Vista or 7 appears to be running Git Bash using
Run as administrator (or disabling UAC for the Git Bash shortcut...or disabling UAC entirely). The difference is night and day and using git on 7 is awesome again.