I have a similar problem. I'm running esxi 6.7 at home, for some simple VMs, on an Asrock Fatal1ty X399 Professional Gaming motherboard with a 16-core AMD ThreadRipper CPU.
My best research shows that all the SATA ports hang off the x399 chipset. That's gotta be what driver is needed. Right?

I was using esxi 7, but the SATA wouldn't load at all. So I wiped the drive and installed 6.7. With vmw_ahci disabled, the local drives are not loaded at all, but with it enabled they all seem to get max read/write around 40MBps.
I'm trying to use an HP SSD S700 for the local VM system drives, and NFS on Unraid (3TB platter x for data drives. For throughput, the NFS is almost as fast as the local drives! The latency of the local drives is much faster, so even with 40MBps it's better on the local SSD. I'd really like to get closer to the 500MBps this drive was getting with Hyper-V.
Anyone have any new ideas?