User Guide
Table Of Contents
- Dell PowerEdge R720 and R720xd Owner's Manual
- About Your System
- Using The System Setup and Boot Manager
- Installing System Components
- Recommended Tools
- Front Bezel (Optional)
- Opening And Closing The System
- Inside The System
- Cooling Shroud
- System memory
- Hard Drives
- Removing A 2.5 Inch Hard-Drive Blank
- Installing A 2.5 Inch Hard-Drive Blank
- Removing A 2.5 Inch Hard-Drive Blank (Back)
- Installing A 2.5 Inch Hard-Drive Blank (Back)
- Removing A 3.5 Inch Hard-Drive Blank
- Installing A 3.5 Inch Hard-Drive Blank
- Removing A Hot-Swap Hard Drive
- Installing A Hot-Swap Hard Drive
- Removing A Hard Drive From A Hard-Drive Carrier
- Installing A Hard Drive Into A Hard-Drive Carrier
- Optical Drive (Optional)
- Cooling Fans
- Internal USB Memory Key (Optional)
- PCIe Card Holder
- Top Cover Lock Latch
- Cable Retention Bracket
- Expansion Cards And Expansion-Card Risers
- Expansion Card Installation Guidelines
- Removing An Expansion Card From The Expansion-Card Riser 2 Or 3
- Installing An Expansion Card Into The Expansion-Card Riser 2 Or 3
- Removing An Expansion Card From The Expansion-Card Riser 1
- Installing An Expansion Card Into The Expansion-Card Riser 1
- Removing Expansion-Card Risers
- Installing Expansion-Card Risers
- GPU Card Installation Guidelines
- Installing A GPU Card
- Removing A GPU Card
- SD vFlash Card
- Internal Dual SD Module
- Internal SD Card
- Integrated Storage Controller Card
- Network Daughter Card
- Processors
- Power Supplies
- System Battery
- Hard-Drive Backplane
- Control Panel Board
- System Board
- Troubleshooting Your System
- Safety First—For You And Your System
- Troubleshooting System Startup Failure
- Troubleshooting External Connections
- Troubleshooting The Video Subsystem
- Troubleshooting A USB Device
- Troubleshooting A Serial I/O Device
- Troubleshooting A NIC
- Troubleshooting A Wet System
- Troubleshooting A Damaged System
- Troubleshooting The System Battery
- Troubleshooting Power Supplies
- Troubleshooting Cooling Problems
- Troubleshooting Cooling Fans
- Troubleshooting System Memory
- Troubleshooting An Internal USB Key
- Troubleshooting An SD Card
- Troubleshooting An Optical Drive
- Troubleshooting A Tape Backup Unit
- Troubleshooting A Hard Drive
- Troubleshooting A Storage Controller
- Troubleshooting Expansion Cards
- Troubleshooting Processors
- Using System Diagnostics
- Jumpers And Connectors
- Technical Specifications
- System Messages
- Getting Help

Processor 1 channel 0: slots A1, A5, and A9
channel 1: slots A2, A6, and A10
channel 2: slots A3, A7, and A11
channel 3: slots A4, A8, and A12
Processor 2 channel 0: slots B1, B5, and B9
channel 1: slots B2, B6, and B10
channel 2: slots B3, B7, and B11
channel 3: slots B4, B8, and B12
The following table shows the memory populations and operating frequencies for the supported configurations.
DIMM Type DIMMs Populated/
Channel
Operating Frequency (in MT/s) Maximum DIMM Rank/
Channel
1.5 V 1.35 V
UDIMM ECC 1 1600, 1333, 1066, and
800
1600, 1333, 1066 and 800 Dual rank
2 1600, 1333, 1066, and
800
1600, 1333, 1066 and 800 Dual rank
RDIMM 1 1866, 1600, 1333, 1066,
and 800
1600, 1333, 1066, and 800 Dual rank
1333, 1066 and 800 1066 and 800 Quad rank
2 1866, 1600, 1333, 1066,
and 800
1600, 1333, 1066, and 800 Dual rank
1066 and 800 1066 and 800 Quad rank
3 1333, 1066 and 800 1066 and 800 Dual rank
LRDIMM 1 1866, 1600, 1333 and
1066
1600, 1333 and 1066 Quad rank
1600, 1333 and 1066 Not applicable Octal rank
2 1600, 1333 and 1066 1600, 1333 and 1066 Quad rank
1600, 1333 and 1066 Not applicable Octal rank
3 1333 and 1066 1066 Quad rank
1333 and 1066 Not applicable Octal rank
General Memory Module Installation Guidelines
This system supports Flexible Memory Configuration, enabling the system to be configured and run in any valid chipset
architectural configuration. The following are the recommended guidelines for best performance:
• UDIMMs, RDIMMs, and LRDIMMs must not be mixed.
• x4 and x8 DRAM based DIMMs can be mixed. For more information, see Mode-Specific Guidelines.
• A maximum of two UDIMMs can be populated in a channel.
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