Been using 33b6 since it came out and I can say there's nothing changed since b5. I can achieve stable hashrate but with much lower multihash. I'm talking about 570 4gb. I can get ~1000 out of those but only for a couple of minutes. Stable hashrate is around 800-900 (I used to get ~820 using 0.32q). So +20% boost is somewhat artificial for now. But on rx vega it does seem to be stable enough. I'm getting ~1840 per card for 24h+