Hi all,
I got 4 vega cards, 2x56, 2x64. everything was fine until i added the 4th card to my rig. All 4 cards hashed about 1900-2000H/s for ~40seconds, then 1 one the card's hashrate dropped to 1400H/s. So i switched this card to different pcie slot. Then one of other 3 hashrate dropped. Im using TB85 motherboard, 4G ram. What do you recommend to fix this issue?

I assume the motherboard got bottleneck. but i don't know how to solve this issue. please help me