23 PowerEdge R720 and R720xd Technical Guide
Memory speeds of 1600 MT/s, 1333 MT/s, 1066 MT/s, and 800 MT/s are supported on the R720 and 
R720xd, depending on the DIMM types installed and the configuration. All memory on all processors 
and channels run at the same speed and voltage. By default, the systems run at the highest speed 
for the channel with the lowest DIMM voltage and speed. The operating speed of the memory is 
also determined by the maximum speed supported by the processor, the speed settings in the BIOS, 
and the operating voltage of the system. 
Table 9 lists the memory configuration and performance details for the R720 and R720xd, based on 
the population of the number and type of DIMMs per memory channel.