HELP ,Samsung 970 Pro Very slow on ESX 6.5

Samsung 970 Pro Very slow on ESXI 6.5.0 (Build 5310538)

I have HP ML30 gen9 , chip is C236, 

I have done the "esxcli system module set –enabled=false –module=vmw_ahci" and rebooted .

But, Still very slow.

# esxcli software vib list | grep nvme

nvme                           1.2.0.32-2vmw.650.0.0.4564106         VMW     VMwareCertified   2018-10-28

vmware-esx-esxcli-nvme-plugin  1.2.0.10-0.0.4564106                  VMware  VMwareCertified   2018-10-28

# time sh -c "dd if=/dev/zero of=test bs=16k count=640k conv=sync"

655360+0 records in

655360+0 records out

real    0m 40.19s

user    0m 0.00s

sys     0m 0.00s

Thanks

suny