Dell PowerEdge R650 Upgrade Guide: RAM and Storage

Lifecycle and support

No longer sold new. Supported until April 30, 2030 (estimate).

Dates not listed haven't been published by the manufacturer or a reliable third party.

Memory (RAM): registered ECC DDR4 only

The R650 has 32 DDR4 DIMM sockets (288-pin, full-size DIMMs), 16 per CPU, arranged as 8 channels per CPU with 2 slots per channel. With only one CPU fitted, just that CPU's 16 slots work. Supported types are RDIMM, LRDIMM and Intel Persistent Memory 200 series. Registered ECC is required, so consumer memory and UDIMMs will not work.

RDIMMs go up to 64 GB per module (8 GB single rank; 16, 32 or 64 GB dual rank), for 2 TB total with two CPUs or 1 TB with one. LRDIMMs go up to 256 GB per module (128 GB quad rank, 256 GB octa rank), for 8 TB with two CPUs or 4 TB with one. Speeds of 3200, 2933 and 2666 MT/s are listed, and what you get depends on your CPU. Dell rates 3200 MT/s at both one and two DIMMs per channel.

Dell's guidelines show balanced configurations of 2, 4, 8, 12, 16, 24 and 32 DIMMs. Other counts may be unbalanced and slower. Dell's documents disagree on the maximum for Persistent Memory (the figures given are 12 TB, around 10 TB, and 4 TB per CPU for PMem alone), so check the memory guidelines before buying PMem.

Buying tips

• Buy registered ECC DDR4 RDIMMs; skip anything labelled UDIMM or desktop memory.
• Match modules in a balanced count (2, 4, 8, 12, 16, 24 or 32) for best speed.
• Check your CPU model before paying extra for 3200 MT/s modules, since the CPU sets the speed.
• The 128 GB quad-rank LRDIMM is listed in both DDR4-2666 and DDR4-3200 versions, so check the speed rating on the listing.
• Read Dell's rules on mixing rank and capacity before combining RDIMM, LRDIMM and PMem.

Storage: drive bays, boot cards and what fits

Your bay layout is set by the backplane ordered with the server. Options are 4 x 3.5" SAS/SATA (optionally plus 2 x 2.5" bays), 8 x 2.5", or 10 x 2.5" (SAS/SATA, or with NVMe slots, or all-NVMe). Some configurations add 2 rear 2.5" bays. Converting between layouts generally needs different parts, so buy drives to suit the bays you already have.

Supported drives include 3.5" SATA and SAS 7.2K up to 18 TB. In 2.5" form, SATA SSDs go up to 3.84 TB, SAS SSDs up to 15.36 TB, SAS 10K up to 2.4 TB, SAS 15K up to 900 GB, and NVMe Gen4 SSDs up to 7.68 TB (Dell mentions larger enterprise models too). NVMe needs a compatible backplane and controller or cabling. Dell's quoted total for 4 x 3.5" bays is 64 TB, which doesn't match 4 x 18 TB; treat that figure as approximate. Dell's documents don't state a drive thickness limit for 2.5" bays (for example 7 mm versus 15 mm), so check the manual.

For boot drives, Dell's BOSS-S1 or BOSS-S2 card is a proprietary card with hardware RAID and two M.2 SATA SSDs, offered in 240 GB or 480 GB. It is not a standalone M.2 slot, and Dell's documents don't state the M.2 length. There is also a boot-only microSD option with 16, 32 or 64 GB cards. Compatible controllers include PERC H745, H755, H755N, H355, H345, HBA355i, S150, and external H840 and HBA355E. Your riser configuration affects which controllers or NVMe adapters fit.

Buying tips

• Confirm whether your server has a 4 x 3.5", 8 x 2.5" or 10 x 2.5" backplane before ordering drives.
• For NVMe drives, check your backplane and controller or cabling support them first.
• Check the drive thickness limit in the owner's manual before buying 2.5" drives.
• For boot drives, look for Dell BOSS-compatible M.2 SATA drives (240 GB or 480 GB) rather than generic M.2 sticks.
• Don't expect to add a plain M.2 SSD; there is no standalone slot.

How to upgrade

Before you start

• Find your server's service tag and check the exact configuration (backplane type, number of CPUs, controller) in Dell's support pages.
• Back up your data and note any RAID settings before touching drives or controllers.
• Check for BIOS and firmware updates for your server, and read the owner's manual for the exact procedure.
• Have an anti-static wrist strap or other grounding method ready.
• Confirm new memory is registered ECC DDR4 and new drives match your bay type and interface.

Steps

1. Back up and plan
   Back up important data and record your RAID and BIOS settings. Decide which slots or bays you will use; for memory, follow Dell's balanced population guidelines.
2. Power off and unplug
   Shut the server down properly, then disconnect all power cords and any other cables that are in the way.
3. Ground yourself
   Use an anti-static strap or touch bare metal on the chassis before handling parts. Hold memory and drives by their edges.
4. Open the case
   Open the server following the exact disassembly steps in Dell's Installation and Service Manual. Do not force any covers or latches.
5. Install the part
   For memory, seat each module in the correct socket according to Dell's population guidelines. For hot-swap drives, use the carrier and bay for your backplane type. For BOSS cards, microSD cards or controllers, follow the manual's instructions and expansion card guidelines.
6. Close and reconnect
   Refit any covers, shrouds or risers you removed, close the case, then reconnect cables and power.
7. Check that the system sees the part
   Power on and check that the BIOS or system setup shows the new memory total or drive. If a drive is missing or memory is not recognised, power down and re-check seating and compatibility.

Good to know

• Dell's documents disagree on the maximum Persistent Memory capacity (12 TB, around 10 TB, or 4 TB per CPU for PMem alone); check the memory guidelines before buying PMem.
• Dell's 64 TB figure for four 3.5" bays doesn't match 4 x 18 TB; treat it as approximate.
• The 2.5" drive thickness limit and the M.2 length for the BOSS card are not stated in Dell's documents we have; check the owner's manual.
• The docs don't list specific CPU models or CPU upgrade limits, so this guide has no CPU section; verify compatibility with Dell before buying a processor.
• Dell publishes no lifecycle dates for the standalone R650, and third-party sites disagree; check your service tag on Dell's support site for your unit's support expiry.

Frequently asked questions

How much RAM can the Dell PowerEdge R650 take?

With two CPUs and 256 GB LRDIMMs, up to 8 TB. With 64 GB RDIMMs, up to 2 TB. With a single CPU only 16 slots work, so the limits halve to 4 TB (LRDIMM) or 1 TB (RDIMM).

Does the R650 support desktop or UDIMM memory?

No. The R650 only works with registered ECC DDR4, meaning RDIMM or LRDIMM, plus Intel Persistent Memory 200 series.

Can I add an M.2 NVMe SSD to the R650?

Not in a standalone slot. The M.2 option is Dell's BOSS-S1 or BOSS-S2 boot card, which uses two M.2 SATA SSDs (240 GB or 480 GB). NVMe is supported in 2.5" bays on a compatible backplane with the right controller or cabling.

What is the biggest hard drive the R650 supports?

Dell lists 3.5" SATA and SAS 7.2K drives up to 18 TB. In 2.5" bays, SAS SSDs go up to 15.36 TB and NVMe Gen4 SSDs up to 7.68 TB (Dell mentions larger enterprise models too).

Can I change from 3.5-inch bays to 2.5-inch bays?

Generally not without different parts. The bay layout is set by the backplane chosen at purchase, so check what your server has before buying drives.

Can I upgrade the CPU in an R650?

The R650 takes up to two 3rd Gen Intel Xeon Scalable (Ice Lake) processors. Dell's documents we have don't list specific compatible models or limits, so check the manual and spec sheet before buying. Your CPU also determines your memory speed, and a second CPU is what enables the other 16 DIMM slots.

Official documents and references

• PDF Dell PowerEdge R650 spec sheet
  Official summary of CPUs, memory, drive bays and PCIe slots
• PDF Dell PowerEdge R650 technical guide
  Supported drives, backplane options and boot storage
• PDF Dell PowerEdge R650 Installation and Service Manual
  Disassembly steps and memory matrix
• Dell R650 memory specifications
  Module sizes, speeds and capacity limits
• Dell R650 memory module installation guidelines
  Balanced DIMM populations and mixing rules
• Dell R650 expansion card installation guidelines
  Riser layouts and which cards fit