Dell OptiPlex 990 DT vs. HP ProDesk 400 G6 Microtower

Comparison and Differences

Dell_OptiPlex_990_DT.jpg case front and back pannelHP_ProDesk_400_G6_Microtower.jpg case front and back pannel
Model
Form factorDesktopMini Tower
CPU optionsIntel Gen2 i3/i5/i7; Celeron; Pentium;Intel Gen8 i3/i5/i7; Celeron; Pentium;
ChipsetQ67B360
Dedicated GPU *GeForce GTX 1650 Low ProfileGeForce GTX 1660 Super
RAMDIMM DDR3-1333DIMM DDR4-2666
RAM slots42
RAM speed1333 MT/s2666 MT/s
RAM max16 GB64 GB
USB ports(10x)USB-A 2.0; (4x)USB-A 3.0; (4x)USB-A 2.0;
Video portsDisplayPort 1.2; VGA;DisplayPort; VGA;
Other portsRJ45; Hdph; (2x) Mic; Line-Out; Line-In; PS2/COM; Serial; Parallel;RJ45; Headset Line-Out; Line-In;
Optional portsN.A.SD card reader; Serial; Serial and (2x) PS2; DP/HDMI/VGA/USB-C;
SATA ports33
PCI slotsPCIe 2.0 x16; PCIe 2.0 x4; PCIe 2.0 x1;PCIe 3.0 x16; (2x) PCIe 3.0 x1;
M.2 slotsN.A.M.2 2280/2230 M-key (PCIe x4); M.2 2230 (WiFi/BT)
Drive bays3.5in; 2.5in; 5.25in;2.5/3.5in; 3.5in; 5.25in (slim)
PSU250 W180/250/310 W
Weight7.56 kg (16.67 lb)5.47 kg (12.06 lb)
Released20112018
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 DT and HP ProDesk 400 G6 Microtower

If you are looking for a more modern desktop, then you should go with the HP ProDesk 400 G6 Microtower which was released in 2018. 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 HP ProDesk 400 G6 Microtower 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 HP ProDesk 400 G6 Microtower 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

The Dell OptiPlex 990 DT has 4 RAM slots while the HP ProDesk 400 G6 Microtower 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 HP ProDesk 400 G6 Microtower is using the faster 2666 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 HP ProDesk 400 G6 Microtower as it has the ability to run 64 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

Both models have the same amount of USB ports for total count of 8. If this is not enough, using a USB hub is always a viable option. 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.

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.

None of the models has an HDMI port. If your monitor supports only the HDMI interface, you will need to buy an adapter. Such adapters are cheap so nothing to worry about.

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 3 SATA slot(s). Keep in mind that having too few SATA slots might limit your options for connecting additional memory drives.

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 HP ProDesk 400 G6 Microtower. 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 HP ProDesk 400 G6 Microtower has a more powerful one rated at 310 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_DT_motherboard.jpg motherboard layoutHP_ProDesk_400_G6_Microtower_motherboard.jpg motherboard layout