Dell OptiPlex 5090 MT vs. Dell OptiPlex 990 DT

Comparison and Differences

Dell_OptiPlex_5090_MT.jpg case front and back pannelDell_OptiPlex_990_DT.jpg case front and back pannel
Model
Form factorMini TowerDesktop
CPU optionsIntel Gen10&11 i3/i5/i7;Intel Gen2 i3/i5/i7; Celeron; Pentium;
ChipsetQ570Q67
Dedicated GPU *GeForce GTX 1660 SuperGeForce GTX 1650 Low Profile
RAMDIMM DDR4-2666/2933/3200DIMM DDR3-1333
RAM slots44
RAM speed3200 MT/s1333 MT/s
RAM max128 GB16 GB
USB portsUSB 3.1 Type C; (x5) USB-A 3.0; (x4) USB-A 2.0;(10x)USB-A 2.0;
Video ports(4x) Display Port 1.4; (x3) HDMI 2.0b; VGA;DisplayPort 1.2; VGA;
Other portsRJ45; Headset; Line-Out/In;RJ45; Hdph; (2x) Mic; Line-Out; Line-In; PS2/COM; Serial; Parallel;
Optional portsVGA /DisplayPort 1.4/HDMI 2.0b/USB 3.2 Gen2 Type-C Port Alt-mode; SD Card;N.A.
SATA ports43
PCI slotsPCIe 4.0 x16; PCIe 4.0 x4; (x2) PCIe x1;PCIe 2.0 x16; PCIe 2.0 x4; PCIe 2.0 x1;
M.2 slotsM.2 2280/2230 M-key (PCIe 3.0 x4, NVMe); M.2 2230 (WiFi/BT) N.A.
Drive bays(x2) 3.5in; (2x) 2.5in; 5.25in (slim);3.5in; 2.5in; 5.25in;
PSU260/300/360 W250 W
Weight7.24 kg (15.95 lb)7.56 kg (16.67 lb)
Released20212011
Manuallinklink
Price**Check PriceCheck Price

** As an Amazon associate we earn from qualifying purchases.
* Dedicated GPU warning: Check if your particular power supply model has enough power. Additionally some PSUs don't come with an auxiliary PCIe power connector and you may need to buy a SATA to PCIe power adapter.

Differences between Dell OptiPlex 5090 MT and Dell OptiPlex 990 DT

If you are looking for a more modern desktop, then you should go with the Dell OptiPlex 5090 MT which was released in 2021. The Dell OptiPlex 990 DT is older and entered production in 2011.

If you are looking for the smaller form factor the Dell OptiPlex 990 DT is the right one for you. It is smaller than the Dell OptiPlex 5090 MT and will fit more easily under your desk.

Processor

Usually the newer the generation of the CPU, the better the performance and efficiency is. If your budget allows it, you should go with the Dell OptiPlex 5090 MT as it is running a newer generation CPU. This is not to say that Dell OptiPlex 990 DT is bad - it can still run some powerful CPUs, albeit being an older generation.

Memory

Both models have have equal amount of ram slots (4 RAM). Usually two RAM slots are more than enough for most cases. However, the count should be taken into account when planning how much and what combination of RAM you are going to need for your system.

The Dell OptiPlex 5090 MT is using the faster 3200 MT/s RAM. The Dell OptiPlex 990 DT is slower by supporting RAM speeds of up to 1333 MT/s. Additionally, if you will be needing a lot of RAM, better go for the Dell OptiPlex 5090 MT as it has the ability to run 128 GB of RAM. The Dell OptiPlex 990 DT can do a bit less at max 16 GB. Most of the times, this should be sufficient for the majority of users.

Ports

In total the Dell OptiPlex 5090 MT has 10 USB ports. The Dell OptiPlex 990 DT is inferior in this regard and packs 8 USB ports. In any case, if you miss USB ports, you can always purchase a USB hub. What is nice about the Dell OptiPlex 5090 MT, is that it has 3 USB 3.1 port(s) which allows transfer of up to 10Gb/s. Unfortunately, the Dell OptiPlex 990 DT has no such port, thus restricting your transfer speeds significantly. For people who want to use external drives on regular basis, this might be an issue.

DisplayPort is crucial for any desktop machine. It is good to see that both models are featuring DisplayPorts. However, the Dell OptiPlex 5090 MT comes with 4 ports, while the Dell OptiPlex 990 DT has only 1. If you are planning to use multiple monitors, the Dell OptiPlex 5090 MT is the better choice.

The Dell OptiPlex 5090 MT comes with an HDMI port, while the Dell OptiPlex 990 DT does not support the interface. Of course missing HDMI port is something that can be easily fixed with a good adapter (e.g. DisplayPort to HDMI).

SATA ports are placed on the system board and it is where you connect your HDD, SSD and Optical Disk Drives. More SATA slots will allow you to have more drives running at the same time. In this regard the Dell OptiPlex 5090 MT is better equipped as it comes with 4 SATA slot(s), while the Dell OptiPlex 990 DT has 3 slot(s).

If you want the fastest transfer speeds for your SSD, an M.2 interface is crucial. Thus, if the M.2 SSD slot is a mandatory requirement for you, go with the Dell OptiPlex 5090 MT. Sadly, the Dell OptiPlex 990 DT has no such slot, and you will be forced to use the SATA interface instead.

Make sure that the available M.2 slot supports the PCIe (also called NVMe) interface. This is important as there are M.2 slots which support only the inferior SATA III interface. For comparison, the SATA III interface has max speeds of 6Gb/s, while the PCIe 3.0 x4 will support speeds up to 32Gb/s!

Power Supply

Having a Power Supply Unit with high power rating is important, if you are going to use components which require extra power. The Dell OptiPlex 990 DT comes with a decent 250 Watt PSU, but the Dell OptiPlex 5090 MT has a more powerful one rated at 360 Watts. Choosing either one depends on your specific requirements and use case. Also don't forget that some models might have more than one PSU option - try to always get the most powerful one, especially if you plan to upgrade to a powerful GPU.

Motherboard

Dell_OptiPlex_5090_MT_motherboard.jpg motherboard layoutDell_OptiPlex_990_DT_motherboard.jpg motherboard layout