Welcome back Lolliedieb, hope your vacation was both fun and restful.

Your version 0.41 has been running on my Ubuntu 18 rig (HEPTA) without fail for days, now. Undervolted two Vega 54's (to 90w) and two RX 570's (to 80w)

Average speed (5s): 15.4 sol/s | 21.2 sol/s | 9.6 sol/s | 10.0 sol/s Total: 56.2 sol/s
Average speed (5s): 22.2 sol/s | 18.8 sol/s | 10.2 sol/s | 11.4 sol/s Total: 62.6 sol/s
Average speed (5s): 16.6 sol/s | 19.6 sol/s | 9.2 sol/s | 11.6 sol/s Total: 57.0 sol/s
Average speed (5s): 17.0 sol/s | 19.4 sol/s | 10.2 sol/s | 9.6 sol/s Total: 56.2 sol/s
Average speed (5s): 16.2 sol/s | 18.2 sol/s | 12.2 sol/s | 9.6 sol/s Total: 56.2 sol/s
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Average speed (60s): 17.5 sol/s | 18.5 sol/s | 10.0 sol/s | 10.7 sol/s Total: 56.8 sol/s
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I'm looking forward to any performance improvements you can make, though. Good luck!