Dell PowerEdge R640 4xLFF HDD Backplane The Dell PowerEdge R640 4xLFF HDD Backplane is an excellent choice for businesses looking for a reliable and powerful storage solution. This backplane offers four large form factor (LFF) hard disk drive (HDD) slots, allowing for up to 32TB of storage capacity. It is designed to be used with the Dell PowerEdge R640 server, providing a high-performance storage solution for businesses.