Dell OptiPlex 390
Yes. 2 slots, up to 16 GB seen working.
It takes DDR3-1333 full-size sticks (DIMM).
- Slots
- 2 DIMM slots
- Type
- DDR3-1333 240-pin DIMM
- Most seen working
- 16 GB in two or more machines
- Firmware says
- 8 GB maximum (often wrong, so we show what machines run)
- How sure
- 92 of 92 reports show this layout
Worked out from 92 hardware reports of this desktop. Sources and method. Updated 10 Nov 2026.
It takes a 2.5-inch SATA SSD.
The machines in the reports have a SATA controller and the firmware lists 4 SATA ports. A 2.5-inch SATA SSD fits a 2.5-inch bay, or a 3.5-inch bay with an adapter bracket.
- Drive type
- SATA
- SATA ports
- 4 listed by the firmware
From 163 PCI device reports and the firmware's port list. Sources and method. Updated 10 Nov 2026.
Illustration Check the label on the power supply.
We don't have this model's power supply rating. It is printed on the supply's sticker, inside the case next to its fan. Prebuilt desktops often use a supply shaped for their case, so match the shape and the plugs as well as the watts. Small cases take a slim supply.
- Rating
- On the supply's label
How to read a power supply label. Sources and method. Updated 10 Nov 2026.
Illustration Processors seen in these desktops.
Processors in the reports: Core i3-2120 (34), Core i5-2400 (29), Core i3-2100 (10), Pentium G630 (6), Pentium G620 (4), Pentium G640 (3). Prebuilt desktops often only take processors from the generation they shipped with, so stay with the ones listed.
- Seen working
- Core i3-2120, Core i5-2400, Core i3-2100
- How sure
- From 92 reports
From the processor records in 92 hardware reports. Sources and method. Updated 10 Nov 2026.
Illustration It has a full-length (x16) slot for a graphics card.
Cards in the reports: Radeon HD 5000/6000/7350/8350 Series (6), GeForce GT 710 (3), Radeon HD 6450/7450/8450 / R5 230 OEM (2), GeForce 8400 GS Rev. 3 (2), GeForce GT 610 (2), GeForce 210 (2). 60% of these machines report a small case. A small case takes low-profile cards only, and its power supply may not feed a card that needs its own power cable.
- x16 slots
- At least 1, listed by the firmware
- Seen working
- Radeon HD 5000/6000/7350/8350 Series, GeForce GT 710, Radeon HD 6450/7450/8450 / R5 230 OEM
- Case
- 60% report a small case
From 163 PCI device reports and the firmware's slot table. Sources and method. Updated 10 Nov 2026.
Illustration Questions
Can I upgrade the RAM in the Dell OptiPlex 390?
Yes. 2 slots, up to 16 GB seen working. It takes DDR3-1333 full-size sticks (DIMM).
What type of RAM does the Dell OptiPlex 390 use?
DDR3-1333 full-size sticks (DIMM, 240-pin).
How much RAM can the Dell OptiPlex 390 take?
Machines in the reports run up to 16 GB. The firmware reports a maximum of 8 GB, a figure that is often wrong.
What SSD does the Dell OptiPlex 390 take?
It takes a 2.5-inch SATA SSD. The machines in the reports have a SATA controller and the firmware lists 4 SATA ports. A 2.5-inch SATA SSD fits a 2.5-inch bay, or a 3.5-inch bay with an adapter bracket.
What processor can I put in the Dell OptiPlex 390?
Processors seen in these desktops. Processors in the reports: Core i3-2120 (34), Core i5-2400 (29), Core i3-2100 (10), Pentium G630 (6), Pentium G620 (4), Pentium G640 (3). Prebuilt desktops often only take processors from the generation they shipped with, so stay with the ones listed.
Can I add a graphics card to the Dell OptiPlex 390?
It has a full-length (x16) slot for a graphics card. Cards in the reports: Radeon HD 5000/6000/7350/8350 Series (6), GeForce GT 710 (3), Radeon HD 6450/7450/8450 / R5 230 OEM (2), GeForce 8400 GS Rev. 3 (2), GeForce GT 610 (2), GeForce 210 (2). 60% of these machines report a small case. A small case takes low-profile cards only, and its power supply may not feed a card that needs its own power cable.
Is this my desktop?
Check the model name on the front or the label of the case. It should read OptiPlex 390.