I will give it a try with that driver, thanks. Also I didn't do any bios mod because I was afraid of making performance worst instead of getting it better.
Edit:
Finally finished installing the drivers with a clear installation. Claymore now "stop working" as soon it detect all 4 GPUs, I guess it might not work because of the R9 series .... I think I will try just the RX 570 alone to see if the driver would make a difference to the mh/s or work.
Have you checked the quality/performance of your RX 570 with any stress test software (like FurMark) yet? If no, I'd suggest you to do that. If your GPU passes the test, it'll confirm that the problem is with software (like Windows/drivers), not your hardware (GPU).