Dell PowerEdge EL Owner's Manual page 142

Memory
UDIMMs
Minimum RAM
Maximum RAM
LRDIMMs
RDIMMs
UDIMMs
Drives
Hard drives
(PowerEdge R720)
Four–hard-drive systems
Eight–hard-drive systems
Sixteen or eight plus eight–hard-drive systems
Twelve–hard-drive systems
Hard drives
(PowerEdge R720xd)
Twelve plus two–hard-drive systems
Twenty-four plus two–hard-drive systems
142
16 GB single- or dual-ranked
2 GB or 4 GB
2 GB with a single processor
4 GB with two processors
Up to 768 GB (PowerEdge R720xd with 2.5 inch hard-drive
configuration)
Up to 512 GB
Up to 64 GB
Up to four 3.5 inch, internal, hot-swappable SATA hard
drives in hard-drive slots 0 through 3 (hard-drive slots 4
through 7 do not support any hard drives and are installed
with a hard-drive blank).
NOTE: Four–hard-drive systems support software RAID.
For more information on software RAID, see the Dell
PowerEdge RAID Controller (PERC) documentation at
support.dell.com/manuals.
Up to eight 3.5 inch or 2.5 inch, internal, hot-swappable SAS,
SATA, or Nearline SAS hard drives in hard-drive slots 0
through 7.
Up to sixteen 2.5 inch, internal, hot-swappable SAS, SATA,
SATA SSD, or Nearline SAS hard drives in hard-drive slots 0
through 15 or 0 through 7 and 0 through 7.
Up to eight 2.5 inch, internal, hot-swappable SAS, SATA,
SATA SSD, or Nearline SAS hard drives in hard-drive slots 0
through 7 (hard-drive bay 1) and up to four 2.5 inch Dell
PowerEdge Express Flash devices (PCIe SSDs) in hard-drive
slots 0 through 3 (hard-drive bay 2).
Up to twelve 3.5 inch, internal, hot-swappable SAS, SATA,
SATA SSD, or Nearline SAS drives, and two optional 2.5 inch
back-accessible SAS, Nearline SAS, or SSD hard drives in
hard-drive slots 0 through 11 and 12 through 13.
Up to twenty-four 2.5 inch, internal, hot-swappable SAS,
SATA, SATA SSD, or Nearline SAS drives in hard-drive slots
0 through 23 and two optional 2.5 inch back-accessible SAS,