Reason behind suggestion was to get a good mobo. I myself have populated 6 RAM slots and to run all 6 of them at 1600 MHz stable I had to keep 1.65V. So now I run them at 1440 MHz @1.5V stable. If u want to use all RAM slots then invest in good mobo.
One more thing that if you want to use ESX then also check about AMD IOMMU feature and support via BIOS of mobo. This is a mandatory thing but it's good if u get it. Equivalent of AMD IOMMU in Intel is VT-d which is I guess only available on Intel motherboards. Also check whether SATA controller and NIC controller is compatible with ESX or not.