Dell OptiPlex 390 SFF vs. Dell OptiPlex 790 SFF

Comparison and Differences

Dell_OptiPlex_390_SFF.jpg case front and back pannelDell_OptiPlex_790_SFF.jpg case front and back pannel
Model
Form factorSmallSmall
CPU optionsIntel Gen2 i3/i5/i7; Celeron; Pentium;Intel Gen2 i3/i5/i7; Celeron; Pentium;
ChipsetH61Q65
Dedicated GPU *GeForce GTX 1650 Low ProfileGeForce GTX 1650 Low Profile
RAMDIMM DDR3-1333DIMM DDR3-1333
RAM slots24
RAM speed1333 MT/s1333 MT/s
RAM max8 GB16 GB
USB ports(8x)USB-A 2.0; (10x)USB-A 2.0;
Video portsHDMI 1.2; VGA;DisplayPort 1.2; VGA;
Other portsRJ45; Hdph; Line-Out; Line-In and Mic; Mic; PS2/COM;RJ45; Hdph; (2x) Mic; Line-Out; Line-In; PS2/COM; Serial; Parallel;
Optional portsN.A.N.A.
SATA ports23
PCI slotsPCIe 2.0 x16; PCIe 2.0 x1;PCIe 2.0 x16; PCIe 2.0 x4; PCIe 2.0 x1;
M.2 slotsN.A.N.A.
Drive bays3.5in; 5.25in(slim);3.5in; 2.5in; 5.25in(slim);
PSU240 W240 W
Weight5.70 kg (12.57 lb)5.70 kg (12.57 lb)
Released20112011
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 390 SFF and Dell OptiPlex 790 SFF

Both computers, the Dell OptiPlex 390 SFF and the Dell OptiPlex 790 SFF, were released during the same year - 2011.

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

Processor

The two models have the same generation of Intel processors. We think that the 2 generation of Intel Processors have enough power to execute all of the home and office tasks that most people will care to do.

Memory

The Dell OptiPlex 790 SFF has 4 RAM slots while the Dell OptiPlex 390 SFF 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.

None of the desktops has an advantage when it comes to the speed of the RAM being used. Both models support RAM speeds of up to 1333. Additionally, if you will be needing a lot of RAM, better go for the Dell OptiPlex 790 SFF as it has the ability to run 16 GB of RAM. The Dell OptiPlex 390 SFF 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 790 SFF has 10 USB ports. The Dell OptiPlex 390 SFF 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 790 SFF has a DisplayPort. The Dell OptiPlex 390 SFF 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 OptiPlex 390 SFF comes with an HDMI port, while the Dell OptiPlex 790 SFF 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 790 SFF is better equipped as it comes with 3 SATA slot(s), while the Dell OptiPlex 390 SFF has 2 slot(s).

M.2 SSD interface allows you to transfer data with higher speeds compared to the old SATA interface. Unfortunately, neither the Dell OptiPlex 390 SFF, nor the Dell OptiPlex 790 SFF 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

Looking at the Power Supply Unit (PSU) of the two models we don't see any differences. For either of them you get a maximum power of 240 Watts. However be careful, many models have more than one power supply option. When buying your computer, it is a good idea to get a version with the most powerful PSU. This will potentially allow you to upgrade to a more powerful GPU for example.

Motherboard

Dell_OptiPlex_390_SFF_motherboard.jpg motherboard layoutDell_OptiPlex_790_SFF_motherboard.jpg motherboard layout