Dell OptiPlex 990 MT vs. Dell Vostro 3900

Comparison and Differences

Dell_OptiPlex_990_MT.jpg case front and back pannelDell_Vostro_3900.jpg case front and back pannel
Model
Form factorMini TowerMini Tower
CPU optionsIntel Gen2 i3/i5/i7; Celeron; Pentium;Intel Gen4 i3/i5/i7; Pentium; Celeron;
ChipsetQ67H81
Dedicated GPU *GeForce GTX 1650GeForce GTX 1660 Super
RAMDIMM DDR3-1333DIMM DDR3-1600
RAM slots42
RAM speed1333 MT/s1600 MT/s
RAM max16 GB16 GB
USB ports(10x)USB-A 2.0; (6x)USB-A 2.0; (2x)USB-A 3.0;
Video portsDisplayPort 1.2; VGA;HDMI 1.2; VGA;
Other portsRJ45; Hdph; (2x) Mic; Line-Out; Line-In; PS2/COM; Serial; RJ45; Hdph; (2x) Mic; Line-Out; Line-In; PS2
Optional portsParallelN/A
SATA ports44
PCI slotsPCIe 2.0 x16; PCIe 2.0 x4; PCIe 2.0 x1;PCIe 2.0 x16; (2x) PCIe 2.0 x1; PCI
M.2 slotsN.A.N.A.
Drive bays(2x) 3.5in; (2x) 2.5in; (2x) 5.25in;3.5in; 5.25in;
PSU265 W300 W
Weight8.87 kg (19.55 lb)8.50 kg (18.73 lbs)
Released20112014
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 990 MT and Dell Vostro 3900

If you are looking for a more modern desktop, then you should go with the Dell Vostro 3900 which was released in 2014. The Dell OptiPlex 990 MT is older and entered production in 2011.

Both models have the same form factor, meaning reoughtly they have the same phiysical size and form.

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 Vostro 3900 as it is running a newer generation CPU. This is not to say that Dell OptiPlex 990 MT is bad - it can still run some powerful CPUs, albeit being an older generation.

Memory

The Dell OptiPlex 990 MT has 4 RAM slots while the Dell Vostro 3900 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 Vostro 3900 is using the faster 1600 MT/s RAM. The Dell OptiPlex 990 MT is slower by supporting RAM speeds of up to 1333 MT/s. In addition, you will be able to install the same amount of RAM in both models, and most probably 16 GB of RAM will be enough for most people. However, if you will be needing more RAM, make sure to check other desktop models too.

Ports

In total the Dell OptiPlex 990 MT has 10 USB ports. The Dell Vostro 3900 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. 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.

Unfortunately, only the Dell OptiPlex 990 MT has a DisplayPort. The Dell Vostro 3900 does not have one? Don't worry though, nowadays video adapters are cheap and you can get almost any combination of conversion types.

The Dell Vostro 3900 comes with an HDMI port, while the Dell OptiPlex 990 MT 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 slots are located on the motherboard and it is where SSD, HDD and Optical Disk Drives are connected. Each of the two models being compared have 4 SATA slot(s). Keep in mind that having too few SATA slots might limit your options for connecting additional memory drives.

M.2 SSD interface allows you to transfer data with higher speeds compared to the old SATA interface. Unfortunately, neither the Dell OptiPlex 990 MT, nor the Dell Vostro 3900 has one. However, you can still use a SATA SSD drive which should give you satisfactory performance.

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 MT comes with a decent 265 Watt PSU, but the Dell Vostro 3900 has a more powerful one rated at 300 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_MT_motherboard.jpg motherboard layoutDell_Vostro_3900_motherboard.jpg motherboard layout