Dell Inspiron 3668 vs. Dell OptiPlex 390 SFF

Comparison and Differences

Dell_Inspiron_3668.jpg case front and back pannelDell_OptiPlex_390_SFF.jpg case front and back pannel
Model
Form factorMini TowerSmall
CPU optionsIntel Gen6 i3/i5/i7; Celeron; Pentium;Intel Gen2 i3/i5/i7; Celeron; Pentium;
ChipsetH110H61
Dedicated GPU *GeForce GTX 1650 SuperGeForce GTX 1650 Low Profile
RAMDIMM DDR4-2133/2400DIMM DDR3-1333
RAM slots22
RAM speed2400 MT/s1333 MT/s
RAM max16 GB8 GB
USB ports(2x) USB-A 3.0; (4x) USB-A 2.0;(8x)USB-A 2.0;
Video portsHDMI 1.2; VGA;HDMI 1.2; VGA;
Other portsRJ45; Hdph; Mic; Line-Out; Line-In; Card Reader;RJ45; Hdph; Line-Out; Line-In and Mic; Mic; PS2/COM;
Optional portsN.A.N.A.
SATA ports52
PCI slotsPCIe 2.0 x16; (2x) PCIe 2.0 x1;PCIe 2.0 x16; PCIe 2.0 x1;
M.2 slotsM.2 2230 (WiFi/BT)N.A.
Drive bays(2x) 2.5in; 3.25in; 9.5mm3.5in; 5.25in(slim);
PSU240 W240 W
Weight5.90 kg (13.01 lb)5.70 kg (12.57 lb)
Released20162011
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 Inspiron 3668 and Dell OptiPlex 390 SFF

If you are looking for a more modern desktop, then you should go with the Dell Inspiron 3668 which was released in 2016. The Dell OptiPlex 390 SFF is older and entered production in 2011.

If you are looking for the smaller form factor the Dell OptiPlex 390 SFF is the right one for you. It is smaller than the Dell Inspiron 3668 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 Inspiron 3668 as it is running a newer generation CPU. This is not to say that Dell OptiPlex 390 SFF is bad - it can still run some powerful CPUs, albeit being an older generation.

Memory

Both models have have equal amount of ram slots (2 RAM). Usually two RAM slots are more than enough for most cases. However, the count should be taken into account when planning how much and what combination of RAM you are going to need for your system.

The Dell Inspiron 3668 is using the faster 2400 MT/s RAM. The Dell OptiPlex 390 SFF 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 Inspiron 3668 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 390 SFF has 8 USB ports. The Dell Inspiron 3668 is inferior in this regard and packs 6 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.

Nowadays, almost every new computer comes equipped with a DisplayPort. However, none of the devices being compared here has one. Don't worry though, DisplayPort adapters are very cheap and you can get virtually any combination of conversion types.

In case your monitor supports HDMI only, you will be happy to hear that both models come with an HDMI port.

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 Inspiron 3668 is better equipped as it comes with 5 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 Inspiron 3668 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_Inspiron_3668_motherboard.jpg motherboard layoutDell_OptiPlex_390_SFF_motherboard.jpg motherboard layout