Since v.466a seems to be more stable, see if the Low Latency Mode (in Broadcast Setting of v.47a )is turned off. With low latency mode on, I noticed getting a flash of yellow every 10 seconds or so on the green bar(bottom of OBS window) when I streaming. The viewers said my stream was lagging, but then it's fine after turning it off. I've forgotten its been known to drop frames, read it about it on the forums.
Dunno if Low Latency is on by default but I believe that's why people say v.466a works, since Low Latency Mode isn't in that version. There could be other things at hand, (x264 profile levels+cpu capabilities added in the log) but this is the only thing I can notice based on performance.