Just want to report back with the status of using 5.8b/c for AMD 6600 (non-XT). When using 5.7c, I had 32% stales and 1.11% incorrect shares in 24 hours. With 5.8b, both are reduced to 0.12% and 0%. AMD driver is 21.10.2 on Windows 10. Thank you, PhoenixMiner!