I have a 8 x [RX480 8G GPU] rig and mining works fine when I'm mining Monero, or Ethereum. But when I switch to ZenCash, the rig crashes in the first 3 minutes.

All the cards were modded with atiflash - copying the 1750 timing strap to the 2000 strap. Is this the cause for it to fail? Should I revert back the mod on the card bios?

Can you please help?