Fixing races generally means stricter synchronization, which makes for slower code. The world is complex and there are always exceptions, but I'd expect performance to decrease.
Edit: it goes without saying, but it's much better to fix the race conditions, regardless of what it means for performance. Some people seem to think I'm advocating for not fixing them.
Edit: it goes without saying, but it's much better to fix the race conditions, regardless of what it means for performance. Some people seem to think I'm advocating for not fixing them.