Dell PowerEdge 2550 Upgrade Guide: RAM, Drives and CPU

Updated Oct. 9, 2026 · Written from this device's verified specifications

This guide covers memory and drive upgrades for the Dell PowerEdge 2550, a 2U Pentium III-era rack server, and explains what to check before buying CPUs. The short answer: it takes up to 4 GB of PC133 registered ECC SDRAM in matched pairs and hot-plug Ultra3 SCSI drives only, so SATA, SAS and SSD upgrades don't apply.

At a glance

  • RAM: 4 DIMM sockets, up to 4 GB total, 168-pin PC133 registered ECC SDRAM (not DDR), installed in like pairs.
  • Storage: 4 hot-plug 1-inch Ultra3 (U160) SCSI bays, plus a fifth in the media bay with a Dell kit.
  • No SATA, SAS, M.2, NVMe or 2.5-inch drive support.
  • CPU: up to two Pentium III processors from 933 MHz to 1.4 GHz; Dell's documents we found don't name the socket type.
  • The RAID cache module is a separate, unbuffered memory type. Don't mix it up with system RAM.
168-pin DIMM (PC133 registered ECC SDRAM)4 × DIMM · up to 4 GB total · 133 MT/s · registered (RDIMM) · ECC
1-inch hot-plug SCSI drive bay4 × HDD 3.5"
4 × DIMMup to 4 GB total1-inch hot-plug SCSI drive bay4 × HDD 3.5"
Schematic of the upgradeable slots (not to scale). Check the owner's manual for their exact positions.

Lifecycle and support

Manufacturer support ended on July 1, 2007 (estimate).

20012003200520072009201120132015201720192021202320252027Today11 · Release · March 27, 200122 · Extended support ends · July 1, 2007
Filled dots: dates published by the manufacturer. Hollow dots: estimates from third-party sources.
MilestoneDate
Release
First available to buy.		 March 27, 2001 Estimate Computerworld (26 March 2001) says the servers 'will be available on March 27'. This is press coverage, not Dell's own statement. CNET says April 2001.
Source ↗
End of extended support
Paid extended support ends; after this there is no manufacturer support at all.		 July 1, 2007 Estimate EOSL (end of support life) date from third-party reseller Pre Rack IT. Extended Tech Solutions gives the same date. Dataknox lists 2008-12-27 instead, marked 'Date Not Published'.
Source ↗

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

Memory: PC133 registered ECC SDRAM, up to 4 GB

The PowerEdge 2550 has 4 DIMM sockets, arranged as 2 banks of 2. It uses 168-pin, 3.3 V, full-size PC133 registered ECC SDRAM DIMMs running at 133 MHz. This is plain SDRAM, not DDR of any generation, and SO-DIMMs won't fit. Dell's spec sheet gives a range of 128 MB up to 4 GB for the whole line.

Modules must be installed in like pairs. Registered and ECC are both required, so unbuffered or non-ECC modules won't work. Dell doesn't state a per-module limit directly. With 4 GB across 4 sockets, 1 GB per module is the practical maximum, and a memory reseller lists 256 MB, 512 MB and 1 GB modules for this server. That pairing rule and the 1 GB figure come from the reseller rather than from Dell, so treat them as strong guidance and check them against the full owner's manual.

The RAID controller's cache memory is a separate socket. It needs unbuffered memory rated for 100 MHz or faster, and registered system DIMMs are not a substitute.

Buying tips

  • Buy PC133 registered ECC 168-pin DIMMs only.
  • Buy modules in matched pairs, such as 2 x 512 MB or 2 x 1 GB.
  • Ignore any listing that says DDR for this server. One parts listing titled it that way, but Dell's spec sheet says SDRAM.
  • If you want RAID cache memory, shop for it separately. It is unbuffered, unlike system RAM.
  • Look up the exact bank and slot population order in the Adding Memory section of the full owner's manual. The copies we found were cut off.

Storage: hot-plug SCSI drives only

The server has 4 front hot-plug drive bays for 1-inch-tall SCSI drives. A fifth 1-inch hot-plug SCSI drive can go in the media bay if you add Dell's upgrade kit. The drives are Ultra3 (U160) SCSI. SATA, SAS, M.2, NVMe and 2.5-inch drives are not supported, so a modern SSD is not an option here.

Dell's spec sheet lists 18 GB, 36 GB and 73 GB drives at 10,000 rpm, plus 18 GB at 15,000 rpm. Its maximum capacity is 365 GB (5 x 73 GB). That is the most Dell shipped, not a tested limit, and nothing we found says whether larger drives work.

The backplane normally runs as a single channel of four drives from one host adapter on connector SCSIA. Splitting it into two channels of two needs Dell's optional SCSI backplane daughter card. In split mode, SCSIB controls slots 0 and 1, while SCSIA controls slots 2 and 3 and the fifth slot (SCSI 4). The spec sheet lists embedded dual-channel Ultra3 SCSI RAID as enablement optional, and the manual also covers an optional Dell PERC host adapter card. Check whether your unit has RAID enabled or needs a PERC card.

Buying tips

  • Buy only hot-plug Ultra3 (U160) SCSI drives, and confirm the connector type with the seller.
  • Make sure the drive comes with its sled or tray, since this is hot-plug hardware.
  • Drives over 73 GB aren't documented for this model. Treat 365 GB total as the safe published figure.
  • A fifth drive needs Dell's upgrade kit, and split-backplane operation needs the optional daughter card.
  • Don't buy SATA, SAS or 2.5-inch drives, as they won't work.

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How to upgrade

Before you start

  • Find your Dell Hardware Owner's Manual. It has the exact disassembly and memory population details.
  • Check which CPU speed your server has (933 MHz to 1.4 GHz). Models differ, but the 4 GB memory maximum applies to the whole line.
  • Work out whether your RAID is embedded, enabled or on a PERC card before buying drives or cache memory.
  • Back up all important data, and confirm the backup restores.
  • Have the new parts ready, and use an anti-static wrist strap and a clean work surface.
  • Remember that the operating systems Dell lists are NetWare 5.1, Windows NT 4.0, Windows 2000 and Red Hat Linux 7.1/7.2. Anything newer is unsupported.

Steps

  1. Back up your data
    Make a full backup of the server, especially before changing drives or RAID settings.
  2. Shut down, power off and unplug
    Shut the operating system down properly, switch the server off, and unplug the power cords and any other cables.
  3. Ground yourself
    Put on an anti-static wrist strap or touch bare metal on the chassis before handling parts. Hold DIMMs by their edges.
  4. Open the case
    Follow the owner's manual to open the server. If it is rack-mounted, slide it out or remove it as the manual describes.
  5. Install memory
    Fit PC133 registered ECC DIMMs in matched pairs, following the bank and slot order in the Adding Memory section of the manual. Keep the RAID cache module, which is unbuffered, separate from system memory.
  6. Install drives
    Hot-plug SCSI drives mount in sleds in the front bays. For a fifth drive in the media bay, use Dell's upgrade kit and follow its instructions. Check the owner's manual for how your SCSI backplane is configured.
  7. Close up and reconnect
    Refit the cover, return the server to the rack if needed, and reconnect the cables and power.
  8. Check that the server sees the new parts
    Power on and watch the startup screen to confirm the memory total is correct. Then check that the SCSI or RAID controller lists the new drives. If a part is missing, power off and re-seat it.

Good to know

  • The pair rule and the 1 GB per-module limit come mainly from a third-party memory reseller, not from Dell. Check them in the full owner's manual before ordering.
  • Dell's documents we found don't name the CPU socket type or maximum power rating, so we can't say which processors are compatible. Check Dell's owner's manual before buying CPUs.
  • Dell's 365 GB storage figure reflects the drives available when the server shipped, not a tested controller limit.
  • One parts listing describes the memory as DDR, which conflicts with Dell's spec sheet. We treat the listing as an error.
  • The spec sheet's PCI count of seven includes embedded devices. Only three full-length 64-bit/33 MHz PCI slots are physically free.
  • The manual copies we found are incomplete, so confirm exact memory slot order and disassembly steps in the full Dell manual.

Frequently asked questions

How much RAM can the Dell PowerEdge 2550 take?

Up to 4 GB total across 4 DIMM sockets. Dell's spec sheet gives a range of 128 MB to 4 GB. Modules go in like pairs, and 1 GB per module is the practical maximum.

What type of memory does the PowerEdge 2550 use?

168-pin, 3.3 V, PC133 registered ECC SDRAM DIMMs. It is not DDR, and unbuffered or non-ECC modules won't work.

Can I put an SSD or SATA drive in a PowerEdge 2550?

No. The drive bays take hot-plug Ultra3 (U160) SCSI drives only. SATA, SAS, M.2 and 2.5-inch drives are not supported.

What is the largest hard drive the PowerEdge 2550 supports?

Dell lists 73 GB drives, and its maximum is 365 GB (5 x 73 GB). That is the most Dell shipped, not a tested limit. Larger drives aren't documented for this server.

Can I upgrade the CPUs in a PowerEdge 2550?

The server takes up to two Pentium III CPUs, from 933 MHz to 1.4 GHz. Dell's documents we found don't name the socket type or maximum power rating, so check Dell's Hardware Owner's Manual before buying any processor.

Can I add a fifth hard drive?

Yes, one more 1-inch hot-plug SCSI drive can go in the media bay with a Dell upgrade kit. It appears as SCSI ID 4.

Official documents and references

This guide was written with AI assistance from the compatibility data PartsPrices verified against the manufacturer's documents. Always check your exact model and the owner's manual before buying or opening your computer.