Dell PowerEdge 1550 Upgrade Guide: RAM, Storage and CPU

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

This guide covers upgrading memory and storage in the Dell PowerEdge 1550, a 1U Pentium III-era server, and what to know before swapping a processor. The short answer: buy PC133 registered ECC memory in matched pairs, plan around 2 GB total, use SCSI drives only, and check CPU speed support before buying a faster processor.

At a glance

  • RAM: 4 DIMM sockets, PC133 registered ECC SDRAM, installed in matched pairs.
  • Dell documents 2 GB maximum; 4 GB (4 x 1 GB) is only claimed by a reseller.
  • Storage: 3 hot-plug 1-inch SCSI bays on a dual-channel Ultra160 controller. No SATA or SAS.
  • CPU: socketed Socket 370 Pentium III, up to two. Dell says up to 1 GHz; a reseller lists 1.4 GHz.
  • A terminator module must fill PROCESSOR2 if only one CPU is fitted.
DIMM socket (PC133 registered ECC SDRAM)4 × DIMM · up to 2 GB total · 133 MT/s · registered (RDIMM) · ECC
Hot-plug 1-inch SCSI drive bay3 × HDD 3.5"
4 × DIMMup to 2 GB totalHot-plug 1-inch SCSI drive bay3 × 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).

2002200420062008201020122014201620182020202220242026Today11 · End of sale · July 1, 200222 · Extended support ends · July 1, 2007
Filled dots: dates published by the manufacturer. Hollow dots: estimates from third-party sources.
MilestoneDate
End of sale
No longer sold new by the manufacturer (Dell calls this 'End of Life', Lenovo 'Withdrawn').		 July 1, 2002 Estimate Third-party date from Relutech, which labels it EOL (Dell's term for end of sale). Only Relutech gives it and it may be a batch date shared with other models.
Source ↗
End of extended support
Paid extended support ends; after this there is no manufacturer support at all.		 July 1, 2007 Estimate Third-party EOSL date on which several sources agree (Park Place, Extended Tech Solutions, globaltpm, Relutech). No separate standard vs. extended support date is published.
Source ↗

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

Memory (RAM)

The 1550 has four DIMM sockets arranged as two banks of two. It uses full-size PC133 registered ECC SDRAM. This is not DDR, and ordinary desktop or unbuffered modules will not work. Modules must be installed in matched pairs, with the same size and type in each bank.

Dell's documentation gives 2 GB as the maximum, and mentions 4 GB once 1 GB DIMMs became available. A memory reseller lists 4 GB (4 x 1 GB), but we could not confirm that against a Dell page, and it may need a later BIOS. Treat 2 GB as the safe ceiling unless you can test 1 GB modules yourself.

One quirk: if you fill all four sockets with DIMMs of the same density, Dell's diagnostics cannot tell you which DIMM is faulty.

Buying tips

  • Buy PC133 registered ECC SDRAM DIMMs, sold as a matched pair.
  • Do not buy desktop, unbuffered or DDR modules.
  • Don't count on 4 GB without a return option in case it doesn't work.
  • Check Dell's support page for a BIOS update before installing larger modules.

Storage (SCSI drives)

The 1550 has three hot-plug bays for 1-inch SCSI hard drives, run by an embedded dual-channel Ultra160 (Ultra3) SCSI controller. An optional PERC3/DCL card adds RAID. There is no SATA, SAS, M.2 or NVMe support, so a modern SSD will not connect directly.

Dell's documents don't state a maximum drive capacity. The bays are described as 1-inch, which in practice means 3.5-inch SCSI drives, although Dell's text doesn't spell out the form factor. One listed factory configuration shipped with a 36.4 GB drive, but that is a shipped configuration, not a limit.

If you add a RAID card, mind the expansion slots. There are two 64-bit/66 MHz PCI slots on separate buses. With one processor you can fit one full-length and one short card. With two processors both cards must be short. Dell does not support 5V PCI cards in this system, even with the optional 5V riser.

Buying tips

  • Buy SCSI drives only, and confirm they come with hot-plug carriers.
  • Check that any RAID card is compatible with the 1550 before buying.
  • Avoid 5V PCI cards; Dell does not support them here.
  • Expect used drives to be well worn.

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How to upgrade

Before you start

  • Find the PowerEdge 1550 User's Guide and read Chapter 8, Installing System Board Options, which covers memory, processors, expansion cards and SCSI devices.
  • Check Dell's support page for BIOS and firmware updates, since faster CPUs and larger DIMMs may need them. We couldn't see specific version numbers.
  • Back up your data and note your current BIOS and RAID settings.
  • This is a 2001-era server, so fans, batteries and drives may be worn. Check their condition while you have the case open.

Steps

  1. Back up and prepare
    Back up all important data. If you are changing drives or a RAID setup, make sure you have a restore plan.
  2. Update the BIOS if needed
    If you are adding larger memory or a faster CPU, install any relevant BIOS or firmware update from Dell's support page first.
  3. Power off and unplug
    Shut the server down fully and disconnect the power cords and all cables.
  4. Ground yourself
    Use an anti-static wrist strap or touch bare metal on the chassis before handling components, and hold parts by their edges.
  5. Open the case and install the part
    Follow the owner's manual for exact disassembly. For memory, fit DIMMs in matched pairs, bank by bank. For a CPU, if only one processor is fitted, a terminator module must stay in PROCESSOR2. Remember that a full-length riser card blocks the second CPU. SCSI drives go in the hot-plug bays; the manual covers the carrier details.
  6. Close up and reconnect
    Refit the cover, reconnect cables and power, and switch the server on.
  7. Check that the system sees the part
    Watch the startup screens and open the BIOS setup to confirm the new memory, processor or drive is detected. If memory is missing or errors appear, recheck the pairing and seating.

Good to know

  • Dell's documented maximum is 2 GB of RAM. The 4 GB figure is unverified.
  • CPU speed support is unclear: Dell's manual says up to 1 GHz, while a reseller lists 1.4 GHz. Verify before buying.
  • Dell's documents don't give a maximum SCSI drive capacity or a maximum CPU power rating.
  • Dell doesn't clearly state the bay form factor; the 1-inch bays are understood to take 3.5-inch SCSI drives.
  • This is an old server. Fans, batteries and drives may be worn, so check their condition.

Frequently asked questions

How much RAM can the Dell PowerEdge 1550 take?

Dell documents 2 GB with four sockets. Dell's text also mentions 4 GB once 1 GB DIMMs became available, and a reseller lists 4 GB (4 x 1 GB), but this is unverified and may need a later BIOS. Plan on 2 GB.

What type of memory does the PowerEdge 1550 use?

PC133 registered ECC SDRAM DIMMs, installed in matched pairs. It is not DDR, and desktop or unbuffered modules should not be used.

Can I use a SATA or SSD drive in the PowerEdge 1550?

Not directly. The bays are for SCSI drives on an Ultra160 controller, with no SATA, SAS or NVMe support. Dell doesn't document a maximum drive size.

What CPUs does the PowerEdge 1550 support?

It has Socket 370 (FC-PGA) sockets for up to two Pentium III processors. Dell's manual says up to 1 GHz, while a reseller lists 1.4 GHz and a 1.13 GHz configuration exists, so verify before buying a faster chip.

Do I need to fill the second CPU socket?

If you run one CPU, a terminator module must fill the PROCESSOR2 socket. A full-length riser card also blocks the second CPU.

Can I add a RAID card?

An optional PERC3/DCL RAID card is part of the 1550 range. Mind the PCI slot layout: a full-length card in the PCI2 position prevents fitting a second processor, and 5V PCI cards are unsupported.

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.