A Discovery user recently bumped into a Windows "feature" that had the unhappy effect of forcing the normally zippy Shazzam probe to slow itself way down — by a factor of over 100. Yikes! What has Microsoft foisted upon us this time?

It's called "concurrent, incomplete outbound TCP connection attempt limiting". This feature is on by default in Windows XP SP2 and up, and off by default on Windows Vista. We haven't found documentation on other Windows versions — if you've got experience with this feature on them, please let us know. To quote Microsoft's TechNet (more here