Dell Inspiron 3647 vs. Dell OptiPlex 390 SFF

Comparison and Differences

Dell_Inspiron_3647.jpg case front and back pannelDell_OptiPlex_390_SFF.jpg case front and back pannel
Model
Form factorSmallSmall
CPU optionsIntel Gen4 i3/i5/i7; Celeron; Pentium;Intel Gen2 i3/i5/i7; Celeron; Pentium;
ChipsetH81 H61
Dedicated GPU *GeForce GTX 1650 Low ProfileGeForce GTX 1650 Low Profile
RAMDIMM DDR3-1333/1600 DIMM DDR3-1333
RAM slots22
RAM speed1600 MT/s1333 MT/s
RAM max16 GB8 GB
USB ports(3x) USB-A 3.0; (6x) USB-A 2.0;(8x)USB-A 2.0;
Video portsHDMI 1.2; VGA;HDMI 1.2; VGA;
Other portsRJ45; Hdph; (2x) Mic; Line-Out; Line-In; 5.1 audio; Card Reader;RJ45; Hdph; Line-Out; Line-In and Mic; Mic; PS2/COM;
Optional portsN.A.N.A.
SATA ports22
PCI slotsPCIe 2.0 x16; PCIe 2.0 x1; mPCIe;PCIe 2.0 x16; PCIe 2.0 x1;
M.2 slotsN.A.N.A.
Drive bays3.5in; 5.25in;3.5in; 5.25in(slim);
PSU220 W240 W
Weight6.0 kg (13.22 lb)5.70 kg (12.57 lb)
Released20132011
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 Inspiron 3647 and Dell OptiPlex 390 SFF

If you are looking for a more modern desktop, then you should go with the Dell Inspiron 3647 which was released in 2013. The Dell OptiPlex 390 SFF 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 Inspiron 3647 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 3647 is using the faster 1600 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 3647 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 Inspiron 3647 has 9 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.

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 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 2 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 390 SFF, nor the Dell Inspiron 3647 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 Inspiron 3647 comes with a decent 220 Watt PSU, but the Dell OptiPlex 390 SFF 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_Inspiron_3647_motherboard.jpg motherboard layoutDell_OptiPlex_390_SFF_motherboard.jpg motherboard layout