I can confirm this. Running 10 RX580s on win10 with drivers 17.11.4 without problems.

@Bakhtra
Can you give me your settings in afterburner if you are using this? afterburner not working for me as it does not recognize more than 8 GPUs and its not working with driver 17.11.4. Hence I am using TRIXX instead (similar tool from Sapphire instead of MSI afterburner).