Dell OptiPlex 7090 SFF Upgrade Guide: RAM, SSD and CPU

Lifecycle and support

A current model: sold new and supported.

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

RAM: four full-size DDR4 slots, up to 128 GB

The OptiPlex 7090 SFF has four memory slots (labelled XMM1 to XMM4). They take full-size, unbuffered DDR4 desktop modules (UDIMMs), not the shorter SO-DIMMs used in laptops. Each slot accepts 4, 8, 16 or 32 GB, the minimum is 4 GB, and the maximum is 128 GB (4 x 32 GB). No memory is soldered to the board, so everything is upgradeable.

Dell's valid layouts are: 16 GB as 2 x 8 GB or 1 x 16 GB; 32 GB as 4 x 8 GB, 2 x 16 GB or 1 x 32 GB; 64 GB as 4 x 16 GB or 2 x 32 GB; and 128 GB as 4 x 32 GB.

Speed is set by your processor. 10th-gen Core i3 and i5 chips run memory at 2666 MT/s, 10th-gen i7 and i9 at 2933 MT/s, and 11th-gen chips are listed at up to 3200 MT/s. Dell's documents are not fully consistent here: one note says 11th-gen systems run memory at 2933 MT/s in dual-channel mode and that speed varies with the number of modules per channel. All of Dell's documents agree that 128 GB configurations run at 2933 MT/s at most. Faster modules than your CPU supports will simply run slower.

Dell's pages also disagree on a few layouts. The spec list shows a 16 GB option made of 4 x 4 GB that the US configuration table does not show. The US table lists a single 64 GB module in XMM1, which looks like an error since 32 GB is the per-slot maximum. Stick to the layouts above.

Buying tips

• Buy 288-pin DDR4 desktop UDIMMs, not SO-DIMMs.
• Choose non-ECC unbuffered modules. Dell's documents don't confirm ECC support.
• Matched pairs (2 x 8 GB, 2 x 16 GB, 2 x 32 GB) are the layouts Dell lists for 16, 32 and 64 GB.
• Don't pay extra for modules faster than your CPU supports: 2666 MT/s on 10th-gen i3/i5, 2933 MT/s on 10th-gen i7/i9.

Storage: two M.2 NVMe slots and SATA drive bays

For a fast SSD, the OptiPlex 7090 SFF has two M.2 slots for NVMe drives. They run at PCIe Gen3 x4 only, so a Gen4 drive will work at Gen3 speed and you gain nothing by paying for it. Dell lists M.2 2230 drives up to 1 TB, M.2 2280 drives up to 2 TB, and M.2 2280 Opal self-encrypting drives up to 1 TB. Dell's product overview also mentions support for Intel Optane memory H20. Dell's service manual shows an M.2 2230 drive held by a single M2x3 screw. Dell's documents don't say which M.2 slot takes which drive length, so check the service manual's drive pages before buying a 2280 drive.

For bulk storage, Dell lists SATA 3.0 drives: 2.5-inch HDDs up to 2 TB (5400 RPM) or 1 TB (7200 RPM), and 3.5-inch HDDs up to 4 TB. A 2.5-inch SATA SSD is also a reasonable fit for the 2.5-inch bay, with Dell's listed maximum being 2 TB for that bay. Dell's regional pages disagree on the 4 TB 3.5-inch drive: the US page lists it at 7200 RPM, while Dell Australia lists 5400 RPM.

Dell's pages don't confirm how many 2.5-inch and 3.5-inch bays your unit has or any drive thickness limit, so check the service manual's drive removal pages. A memory card slot and any extra expansion slot were not confirmed either.

Buying tips

• Pick a Gen3 NVMe SSD. A Gen4 drive costs more and runs no faster here.
• Check the length (2230 or 2280) against the service manual before you buy.
• Dell's 2230 limit is 1 TB; the 2 TB maximum applies to 2280 drives.
• For a self-encrypting Opal drive, Dell lists a 1 TB maximum.
• If you want a 4 TB 3.5-inch drive, expect 5400 or 7200 RPM depending on the listing.

CPU: 65 W Intel 10th and 11th-gen chips

The system uses the Intel Q570 chipset. Dell's documents don't name the socket; 10th and 11th-gen desktop CPUs on this chipset use LGA1200, so the processor should be removable. Confirm this in the service manual before buying.

Dell lists these supported processors, all at 65 W. 10th-gen: Core i3-10105, i3-10305, i5-10400, i5-10500, i5-10505, i5-10600, i7-10700 and i9-10900. 11th-gen: Core i5-11400, i5-11500, i5-11600, i7-11700 and i9-11900. Dell lists 65 W as the maximum, so chips with a higher power rating are not listed. The same Dell document mentions lower-power (35 W) options, so some configurations may ship with a lower-power chip.

Your CPU choice also affects memory speed (see the RAM section). Dell's documents don't say whether a BIOS update is needed before fitting a different generation, so check Dell's support page for your service tag first.

Buying tips

• Choose only from Dell's listed models. Other LGA1200 chips are not confirmed to work.
• Stay at 65 W or below.
• An 11th-gen chip allows faster memory than a 10th-gen i3 or i5.
• Check the power supply of your unit (Dell lists 200 W and 300 W options) before moving to a higher-end chip.

How to upgrade

Before you start

• Find your service tag on the case and check Dell's support page for the exact parts your unit shipped with.
• Download the OptiPlex 7090 SFF service manual from Dell for exact disassembly and part locations.
• Back up your data before changing any storage or opening the case.
• Dell lists only Windows 10 Pro and Ubuntu 20.04 LTS as supported operating systems.
• Have a small screwdriver ready. An M.2 2230 drive uses an M2x3 screw.

Steps

1. Back up your files
   Copy important data to an external drive or cloud storage, especially before swapping or cloning drives.
2. Shut down and unplug
   Shut the computer down fully, then unplug the power cable and any other cables. Hold the power button for a few seconds to drain remaining charge.
3. Ground yourself
   Touch bare metal on the case or use an anti-static wrist strap before handling components. Hold parts by their edges.
4. Open the case
   Follow the removal steps in Dell's service manual to open the case and reach the memory, drive or CPU area.
5. Install the part
   For memory, fit the modules in the slots using one of Dell's listed layouts. For an M.2 drive, seat it in the slot and secure it with the screw as shown in the manual. For a SATA drive, use the drive bay procedure in the service manual. For a CPU, follow Dell's CPU and cooling procedure in the manual.
6. Close the case and reconnect
   Refit the cover, reconnect the cables and power on.
7. Check that the system sees the part
   Press F2 at startup to enter the BIOS setup, or check the system information screen, and confirm the new memory, drive or CPU is listed. A new blank drive will need an operating system installed or a cloned copy.

Good to know

• Dell's documents don't name the CPU socket. LGA1200 is the likely socket, but verify in the service manual.
• Dell's documents don't confirm ECC memory support.
• Dell's pages disagree on 11th-gen memory speed (3200 or 2933 MT/s) and on the RPM of the 4 TB 3.5-inch drive.
• The number of 2.5-inch and 3.5-inch bays, drive thickness limits and which M.2 slot takes which length are not confirmed.
• No memory card slot or extra expansion slot was confirmed.
• Factory CPU and drive options vary by configuration and region, so check your unit's service tag.

Frequently asked questions

How much RAM can the OptiPlex 7090 SFF take?

Up to 128 GB, using four 32 GB DDR4 UDIMMs. The minimum is 4 GB. Note that 128 GB configurations run at 2933 MT/s at most.

Does the OptiPlex 7090 SFF use laptop SO-DIMM memory?

No. It uses full-size desktop DDR4 UDIMMs. Laptop SO-DIMMs won't fit.

Does it support ECC memory?

Dell's documents don't confirm ECC support. Use unbuffered non-ECC modules, or check with Dell if you need ECC.

Can I use a PCIe Gen4 NVMe SSD?

Yes, but the M.2 slots are PCIe Gen3 x4 only, so a Gen4 drive runs at Gen3 speed and gives you no extra performance.

What is the biggest SSD or hard drive it supports?

Dell lists M.2 2280 SSDs up to 2 TB (1 TB for 2230 and Opal self-encrypting drives), 2.5-inch drives up to 2 TB, and 3.5-inch HDDs up to 4 TB.

Can I upgrade the CPU?

Probably. The CPU should be socketed (LGA1200 is the likely socket, though Dell's documents don't name it). Dell lists only 65 W Core i3 to i9 chips from the 10th and 11th generations as supported.

Official documents and references

• PDF Dell OptiPlex 7090 SFF specifications (PDF)
  Supported CPUs, memory speeds, power supply options
• Dell memory configuration matrix
  Valid memory layouts and speed notes
• Dell memory specifications
  Slot count, module sizes and maximum capacity
• Dell storage specifications
  Supported M.2 and SATA drive types and capacities
• Dell product overview
  Dual M.2 slots and Optane H20 support
• Dell service manual: installing the M.2 2230 SSD
  How the 2230 drive is fitted and secured
• Dell Australia product comparison
  Regional drive options, including the 4 TB 3.5-inch drive