Reading Time: 3 minutes Now that the PSOD on vSphere 6.5 and 10 Gbps NICs issue is finally solved seems that vSphere 6.5 critical bugs are closed, but it’s not totally true. During an upgrade from a vSphere 6.0, I’ve found a really strange iSCSI storage issues where all the VMs on the iSCSI datastore were so slow to become un-usable. First I was thinking about drivers or firmware, in the hosts and in the NIC (1 Gbps) or the firmware on the storage.