I'm pretty new to mining. I just assembled my first rig with the following specs:

• AsRock H110 BTC+ Motherboard
• Kingston 4GB DDR4 2133MHz
• 8x AMD RX 470 4GB
• 2x Corsair RMX Serie RM1000x
• Windows 10
• Claymore Miner v10.0
• Crimson ReLive Edition Beta Drivers

Now I face the following problem: As long as I run the Claymore miner with up to 7 GPUs, everything works very smooth and I get 28MHz on every card. When I start the miner with an 8th card, the whole computer freezes after 1-5 hours. I believe to have witnessed a drop on GPU #7 hash rate before the freeze but I'm not 100% sure.

What I tried before:

• Changed the cards / PCIE slots to make sure I don't have a corrupt card
• Started two claymore miners having each work with 4 GPUs
• Changed from (4 GPUS + motherboard) on one power supply and (4 GPUS) on the other power supply to (3 GPUS + motherboard) and (5 GPUS)
• Reinstalled the drivers and used different versions (16 & 19)

Does anyone have the same problem and found a solution?