Dell OptiPlex 5070 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: up to 64 GB of DDR4

The SFF has four full-size DIMM slots and takes non-ECC unbuffered DDR4. Dell lists 16 GB as the largest module and 64 GB (4 x 16 GB) as the maximum. The smallest supported setup is 4 GB. Listed configurations are 4 GB (1 x 4), 8 GB (2 x 4 or 1 x 8), 16 GB (2 x 8 or 1 x 16), 32 GB (4 x 8 or 2 x 16) and 64 GB (4 x 16).

Memory speed depends on your processor. The top speed is 2666 MT/s with a Core i5 or i7. With a Celeron, Pentium or Core i3 the memory runs at 2400 MT/s, so faster modules won't help there. Registered and ECC modules are not listed as supported.

Fit modules in matched pairs. Mixing sizes still works but performance is slightly reduced. The Micro model uses SO-DIMMs and tops out at 32 GB, so ignore listings written for that model.

Buying tips

• Buy DDR4 desktop DIMMs (full size, not SO-DIMM), non-ECC and unbuffered
• Buy two identical modules, such as 2 x 8 GB or 2 x 16 GB
• Check your CPU before paying for 2666 MT/s memory; i3, Pentium and Celeron systems run at 2400 MT/s
• Don't buy modules larger than 16 GB each; that is the largest size Dell lists

Storage: M.2 SSD plus SATA bays

The main SSD slot is an M.2 slot (Socket 3) that takes 2230 or 2280 drives. It accepts either SATA or PCIe NVMe drives, and the slot supports PCIe Gen 3. Dell's documents don't say how many PCIe lanes it has. Dell lists 1 TB as the largest M.2 drive it sells, but larger drives may well work. Don't confuse it with the second, smaller M.2 slot (Socket 1, 2230), which is for the Wi-Fi/Bluetooth card and not for storage.

The internal drive bay holds either one 3.5 inch drive or two 2.5 inch drives, using SATA. Dell lists up to 2 TB for both 3.5 inch and 2.5 inch hard drives and 1 TB for a 2.5 inch SATA SSD, but larger drives may work. Dell's documents don't give a maximum thickness for 2.5 inch drives.

The system has three SATA ports: one SATA 2.0, which the optical drive uses, and two SATA 3.0. Because the bay is shared, you can't fit a 3.5 inch drive and two 2.5 inch drives at once. Dell's manuals also list a 16 GB Intel Optane M.2 module on a PCIe Gen 2 interface.

Buying tips

• For the fastest drive, choose an M.2 NVMe SSD in 2280 or 2230 size
• An M.2 SATA SSD also fits, but it is slower than NVMe
• For a bulk-storage drive, a 3.5 inch SATA drive or two 2.5 inch SATA drives will fit
• Dell's drive size lists are for drives it sells; larger capacities may work but aren't confirmed
• Don't buy a Wi-Fi-sized M.2 card slot adapter for storage; the Socket 1 slot isn't for drives

CPU: 8th and 9th Gen Core, up to 65 W

The CPU is a replaceable part: Dell's service manual has removal and installation procedures for the processor. Dell's documents don't name the socket; these CPUs use LGA1151, so check the processor section of the service manual before buying. The system uses the Intel Q370 chipset and has a single CPU. Older 6th and 7th Gen CPUs aren't supported, and nothing newer than 9th Gen (including 10th Gen and Core i9) is listed.

For the SFF, Dell lists these 65 W CPUs. 9th Gen: Pentium G5420 and G5600, Core i3-9100 and i3-9300, Core i5-9400, i5-9500 and i5-9600, and Core i7-9700 (8 cores). 8th Gen: Core i7-8700, i5-8500 and i5-8400, i3-8300 and i3-8100, Pentium Gold G5500 and G5400, and Celeron G4900. The 35 W T-series versions are listed for the Micro only. They should physically fit, but Dell doesn't list them for the SFF.

Dell labels all of these as offered offline only, meaning factory configurations. Dell doesn't say each one is a validated field upgrade. The SFF uses a proprietary low-profile cooler and power supply, and Dell's documents don't give the power supply wattage or heatsink limits, so stay at or under 65 W. The Q370 chipset doesn't support overclocking, so K-series chips offer no advantage.

The i7-9700 is the top listed option if your BIOS supports 9th Gen. The i7-8700 is the best 8th Gen choice, and the i5-9500 or i5-9600 are lower-cost alternatives. Update the BIOS before swapping the CPU, especially for a 9th Gen chip. Dell's BIOS page says that if you're on a version earlier than 1.3.1, you must update to 1.3.1 before installing 1.5.0 or later. It doesn't state which BIOS version each CPU generation needs.

Buying tips

• Choose a 65 W or lower LGA1151 8th/9th Gen chip from Dell's list, such as the i7-9700 or i7-8700
• Skip K-series and anything 10th Gen or newer
• Update the BIOS before you fit a new CPU
• Remember a Core i3, Pentium or Celeron limits RAM to 2400 MT/s, while an i5 or i7 allows 2666 MT/s

How to upgrade

Before you start

• Back up your files; a drive swap or a BIOS update can lead to data loss if something goes wrong
• If you use BitLocker, suspend it before updating the BIOS and re-enable it afterward
• For a CPU swap, update the BIOS first (see Dell's BIOS page for your model)
• Check your current CPU, RAM and drives in Windows so you know what you're replacing
• Have the owner's or service manual open for exact disassembly steps for the SFF case
• Get an anti-static wrist strap or touch bare metal on the case before handling parts

Steps

1. Back up and update
   Back up important files. If you're changing the CPU, update the BIOS to the latest version first, suspending BitLocker beforehand if it's enabled.
2. Power off and unplug
   Shut the PC down fully, unplug the power cable and any other cables, and hold the power button for a few seconds to discharge leftover power.
3. Ground yourself
   Work on a clean, flat surface and touch bare metal on the chassis before handling components. Hold cards and modules by their edges.
4. Open the case
   Remove the cover following the steps in Dell's owner's or service manual for the OptiPlex 5070 SFF.
5. Install the part
   For RAM, fit modules in matched pairs in the DIMM slots. For storage, fit an M.2 drive in the Socket 3 slot, not the Wi-Fi slot, or fit SATA drives in the drive bay. For a CPU, follow the processor removal and installation procedure in the service manual, and remember the SFF uses a proprietary low-profile cooler.
6. Close the case
   Put any removed shrouds, brackets and cables back as they were, then refit the cover and reconnect the cables.
7. Check that it's detected
   Power on and open the BIOS setup. Confirm the new memory, drive or CPU is listed. If it isn't, power off, unplug and reseat the part. For a new drive, set it up in your operating system.

Good to know

• Dell lists the supported CPUs as factory configurations (offered offline only), not as validated upgrades.
• Dell's documents don't name the CPU socket; these CPUs use LGA1151. Confirm in the service manual's processor section before buying.
• Dell doesn't say which BIOS version each CPU generation needs, so update to the latest BIOS before swapping the CPU.
• Dell lists 1 TB (SSD) and 2 TB (hard drive) maximums only for the drives it sells; larger drives may work but aren't confirmed.
• Dell doesn't document a maximum thickness for 2.5 inch drives or the PCIe lane count of the M.2 slot.
• Dell's documents don't give the power supply wattage or cooler limits for the SFF, so stay at 65 W or below.
• The service manual's general DDR4 page mentions up to 512 GB per module. That describes the memory technology, not this PC; the limit here is 16 GB per module and 64 GB total.
• Dell's specs also cover the Tower and Micro. The Micro uses SO-DIMMs, has a 32 GB maximum and one 2.5 inch bay, so don't apply its limits to the SFF.

Frequently asked questions

How much RAM can the Dell OptiPlex 5070 SFF take?

Up to 64 GB, using four 16 GB DDR4 DIMMs. Dell lists 16 GB as the largest module and 4 GB as the minimum configuration.

What type and speed of RAM does the OptiPlex 5070 SFF use?

Non-ECC unbuffered DDR4 DIMMs. Memory runs at up to 2666 MT/s with Core i5 and i7 CPUs, and at 2400 MT/s with Celeron, Pentium and Core i3 CPUs.

Does the OptiPlex 5070 SFF support NVMe SSDs?

Yes. Its M.2 Socket 3 slot takes 2230 or 2280 drives, either SATA or PCIe NVMe, and supports PCIe Gen 3. Dell's documents don't say how many PCIe lanes the slot has.

Can I upgrade the processor in the OptiPlex 5070 SFF?

Yes, the CPU is a replaceable part. Dell lists 8th and 9th Gen Core, Pentium and Celeron parts up to 65 W, with the Core i7-9700 as the top 9th Gen option and the i7-8700 as the top 8th Gen option. These are factory configurations rather than validated upgrades, so update the BIOS first.

What is the biggest drive the OptiPlex 5070 SFF supports?

Dell lists 2 TB for 3.5 inch and 2.5 inch hard drives and 1 TB for SATA and M.2 SSDs, but that only reflects the drives Dell sells. Larger drives may work, though that isn't confirmed.

Can I fit a 3.5 inch drive and two 2.5 inch drives together?

No. The bay holds either one 3.5 inch drive or two 2.5 inch drives. You can add an M.2 SSD on top of either option.

Official documents and references

• Dell OptiPlex 5070 SFF: Memory specifications
  Memory type, slots, capacity and speed
• Dell OptiPlex 5070 SFF: Storage specifications
  M.2 slot, drive bays and listed drive capacities
• Dell OptiPlex 5070 SFF: Processor specifications
  List of supported CPUs and TDP
• Dell OptiPlex 5070 SFF: Chipset specifications
  Intel Q370 chipset details
• Dell OptiPlex 5070 SFF: Intel Optane memory
  The listed 16 GB M.2 Optane module
• Dell service manual: Installing the M.2 PCIe SSD
  Step-by-step M.2 SSD installation
• Dell service manual: DDR4 memory
  Service manual memory section
• PDF Dell OptiPlex 5070 specification sheet (PDF)
  Full specs for memory, storage, CPUs and BIOS update notes
• Dell OptiPlex 5070 SFF BIOS download
  BIOS versions and update requirements