Dell OptiPlex 5040 MT vs. Dell OptiPlex 990 USFF

Comparison and Differences

Dell_OptiPlex_5040_MT.jpg case front and back pannelDell_OptiPlex_990_USFF.jpg case front and back pannel
Model
Form factorMini TowerUltra Small
CPU optionsIntel Gen6 i3/i5/i7Intel Gen2 i3/i5/i7; Celeron; Pentium;
ChipsetQ170Q67
Dedicated GPU *GeForce GTX 1650 SuperN.A.
RAMDIMM DDR3L-1600 DIMM DDR3-1333
RAM slots42
RAM speed1600 MT/s1333 MT/s
RAM max16 GB8 GB
USB ports(6x) USB-A 3.0; (4x) USB-A 2.0; (7x)USB-A 2.0;
Video ports(2x) Display Port 1.2; HDMI 1.4;DisplayPort 1.2; VGA;
Other portsSerial; (2x) PS2; RJ45; Headset; Line-Out; RJ45; Hdph; (2x) Mic; Line-Out; Line-In; PS2/COM; Serial; Parallel;
Optional portsVGA; Media Card Reader;N.A.
SATA ports42
PCI slotsPCIe 3.0 x16; PCIe 3.0 x16 (wired x4); PCIe 3.0 x1; PCI; N.A.
M.2 slotsM.2 2280 M-key (PCIe 3.0 x4, NVMe) N.A.
Drive bays3.5in/5.25in; (2x) 2.5in; 5.25in (slim);2.5in; 5.25in(slim);
PSU240 W200 W
Weight8.00 kg (17.64 lb)3.27 kg (7.20 lb)
Released20152011
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 5040 MT and Dell OptiPlex 990 USFF

If you are looking for a more modern desktop, then you should go with the Dell OptiPlex 5040 MT which was released in 2015. 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 OptiPlex 5040 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 5040 MT 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 OptiPlex 5040 MT 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 OptiPlex 5040 MT is using the faster 1600 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 OptiPlex 5040 MT as it has the ability to run 16 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 OptiPlex 5040 MT 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. None of the desktop models has a USB 3.1 port (10Gb/s), so if you need a fast connection to your peripherals, like external Solid State Drive, you will need to look elsewhere.

DisplayPort is crucial for any desktop machine. It is good to see that both models are featuring DisplayPorts. However, the Dell OptiPlex 5040 MT comes with 2 ports, while the Dell OptiPlex 990 USFF has only 1. If you are planning to use multiple monitors, the Dell OptiPlex 5040 MT is the better choice.

The Dell OptiPlex 5040 MT 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 OptiPlex 5040 MT is better equipped as it comes with 4 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 OptiPlex 5040 MT. 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 OptiPlex 5040 MT has a more powerful one rated at 240 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_5040_MT_motherboard.jpg motherboard layoutDell_OptiPlex_990_USFF_motherboard.jpg motherboard layout