Comment by skittlebrau

We got way better at dealing with synced/deterministic simulations over time. Much better sync logging system, decoupling render rate from simulation rate, more institutional knowledge/intuition about all the surefire ways to break determinism (using unsynced random number generator, uninitialized variables, reading local machine state from sim, using local timers rather than synced ones, not resetting floating point flags after calling Direct3D, etc). The bad news was once we were generally avoiding all the common causes as a matter of course, the sync bugs that remained were non-trivial ones that took lots of time to diagnose.