Use 2.2, or 3.1. 3.1 supposedly fixes HBCC, which is definitely broken on all the older drivers. Vega Overclocking works very poorly on Wattman compared to OverdriveNTool, and your best option is to set your settings first with OverdriveNTool, then save them again under Wattman manual. Wattman may "forget" your settings sometimes, but they will keep after OverdriveNTool applied then Wattman verified. If it doesn't, the settings aren't 100% stable, which can run some older games fine, but hard crash Vulkan or other new games. Undervolting especially. I have personally tested that settings under 1076mV are not truly stable on my card, and even when it did "work" the GPU had occasional micro-stuttering meaning the OC wasn't really working. Also, Wattman is well known for "forgetting" overclocks after a reboot, so OverdriveNTool is pretty much a requirement for any Vega overclock. Electro-migration is also a thing, so don't think for a second your maximum undervolt is permanent, or stable just because you don't crash. I noticed minor throttling and stutters with "stable" undervolts that didn't crash, and the only fix is raising the voltage until it goes away. Some overclocks may ultimately be impossible due to voltage stability combined with thermal and power limits. Each card has it's own limit. Also, HBM instability will crash more than GPU instability, GPU will just random stutter.
Last years drivers were not really more stable. Stability highly depends on what games and software you were running, and 2.2/3/1 are generally more stable overall, with 3.1 incorporating most of the best bug fixes and performance improvements.
4.1 on the other hand, has been benchmarked to have worse performance than 3.1, not to mention stability regression bugs and is not worth using.
19.10.2 stability is an illusion. The reality is probably closer to that the card is unstable without crashing, and your games aren't taxing the GPU hard enough to lock up, which only works on that version, but you are still going to experience micro stuttering or random downclocks. Vega is ultimately a PITA to OC, and there is no "true" overclock when the thing has such hardcore power throttling built into the GPU with no true method of disabling.
