My personal opinion that for heavy better to use 18.3.1 driver. Blockchain driver is not stable on Heavy with max intensities
do you use PPT on custom cards also or are you on reference cards?
my reference running on blockchain run fine on high intensity about 1280h/s 140w 1407/1100 ? stable 18+ hours
ill try the drivers on my custom cards as the above settings seems to crash and not detect on vega on reboot. I then need to reboot once more for it to show up. (could this be a bios thing perhaps?) I set all to gen2 and above 4g enabled.
EDIT: Tried 18.3.1 - lose around 250h/s a card
my ref cards are on blockchain drivers mining xmr 2000-2100h/s with srbminer.
My non-refs, including Hynix-based Sapphire Pulse Vega 56, are running 18.3.1 and Heavy algo. Hynix are 1450+h/s, Samsung 1500+h/s
All cards are using SoftPowerPlay tables. For blockchain drivers and ref cards it is custom table I posted here some time ago with increased SoC clock.
For non-refs and 18.3.
14 drivers I prepare SoftPowerPlay tables easily with OverdriveNtool on basis of card's own bios.