Dell OptiPlex 990 USFF vs. Dell XPS 8940

Comparison and Differences

Dell_OptiPlex_990_USFF.jpg case front and back pannelDell_XPS_8940.jpg case front and back pannel
Model
Form factorUltra SmallMini Tower
CPU optionsIntel Gen2 i3/i5/i7; Celeron; Pentium;Intel Gen10 & 11 i3/i5/i7;
ChipsetQ67H470
Dedicated GPU *N.A.GeForce RTX 3080
RAMDIMM DDR3-1333DIMM DDR4-2666/2933
RAM slots24
RAM speed1333 MT/s2666 MT/s
RAM max8 GB128 GB
USB ports(7x)USB-A 2.0; USB 3.0 Type C; USB 3.1 Type A; (2x) USB-A 2.0; (7x) USB-A 3.0;
Video portsDisplayPort 1.2; VGA;HDMI 2.0; DisplayPort 1.4;
Other portsRJ45; Hdph; (2x) Mic; Line-Out; Line-In; PS2/COM; Serial; Parallel;RJ45; Mic; Headset; Card Reader;
Optional portsN.A.N.A.
SATA ports23
PCI slotsN.A.PCIe 3.0 x16; PCIe x4; PCIe x1;
M.2 slotsN.A.M.2 2280/2230 M-key (PCIe 3.0 x4, NVMe); M.2 2230 (WiFi/BT);
Drive bays2.5in; 5.25in(slim);(3x) 3.5in;
PSU200 W500 W
Weight3.27 kg (7.20 lb)6.3 kg (13.89 lb)
Released20112020
Manuallinklink
Price**Check PriceCheck Price

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* 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 990 USFF and Dell XPS 8940

If you are looking for a more modern desktop, then you should go with the Dell XPS 8940 which was released in 2020. The Dell OptiPlex 990 USFF is older and entered production in 2011.

If you are looking for the smaller form factor the Dell OptiPlex 990 USFF is the right one for you. It is smaller than the Dell XPS 8940 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 XPS 8940 as it is running a newer generation CPU. This is not to say that Dell OptiPlex 990 USFF is bad - it can still run some powerful CPUs, albeit being an older generation.

Memory

The Dell XPS 8940 has 4 RAM slots while the Dell OptiPlex 990 USFF has only 2 slot(s). This is not something to worry about. Just make sure you take it into consideration when planning how much RAM you are going to use.

The Dell XPS 8940 is using the faster 2666 MT/s RAM. The Dell OptiPlex 990 USFF 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 XPS 8940 as it has the ability to run 128 GB of RAM. The Dell OptiPlex 990 USFF can do a bit less at max 8 GB. Most of the times, this should be sufficient for the majority of users.

Ports

In total the Dell XPS 8940 has 10 USB ports. The Dell OptiPlex 990 USFF is inferior in this regard and packs 7 USB ports. In any case, if you miss USB ports, you can always purchase a USB hub. What is nice about the Dell XPS 8940, is that it has 1 USB 3.1 port(s) which allows transfer of up to 10Gb/s. Unfortunately, the Dell OptiPlex 990 USFF 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.

The DisplayPort is usually the more popular video port used with desktops and laptops, while the HDMI is used predominantly in consumer electronics. That's why, it is good to see that both of the models come with a DisplayPort.

The Dell XPS 8940 comes with an HDMI port, while the Dell OptiPlex 990 USFF 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 XPS 8940 is better equipped as it comes with 3 SATA slot(s), while the Dell OptiPlex 990 USFF has 2 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 XPS 8940. Sadly, the Dell OptiPlex 990 USFF 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 USFF comes with a decent 200 Watt PSU, but the Dell XPS 8940 has a more powerful one rated at 500 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_990_USFF_motherboard.jpg motherboard layoutDell_XPS_8940_motherboard.jpg motherboard layout