Dell OptiPlex 990
Desktop, from 2011 63 hardware reports
Memory
Up to 32 GB
4 full-size slots
Drives and power
Coming next
Checked from separate sources
Upgradable
Yes. 4 slots, up to 32 GB seen working.
It takes DDR3-1333 full-size sticks (DIMM).
- Slots
- 4 DIMM slots
- Type
- DDR3-1333 240-pin DIMM
- Most seen working
- 32 GB in two or more machines
- Firmware says
- 32 GB maximum
- How sure
- 62 of 63 reports show this layout
See 8 GB DDR3-1333 DIMM on AmazonOpens an Amazon search for this exact spec.
Worked out from 63 hardware reports of this desktop. Sources and method. Updated 9 Nov 2026.
4 full-size slots
Illustration Questions
Can I upgrade the RAM in the Dell OptiPlex 990?
Yes. 4 slots, up to 32 GB seen working. It takes DDR3-1333 full-size sticks (DIMM).
What type of RAM does the Dell OptiPlex 990 use?
DDR3-1333 full-size sticks (DIMM, 240-pin).
How much RAM can the Dell OptiPlex 990 take?
Machines in the reports run up to 32 GB. That matches the 32 GB maximum the firmware reports.
Is this my desktop?
Check the model name on the front or the label of the case. It should read OptiPlex 990.