Dell OptiPlex 7040M vs. Dell OptiPlex 790 USFF

Comparison and Differences

Dell_OptiPlex_7040M.jpg case front and back pannelDell_OptiPlex_790_USFF.jpg case front and back pannel
Model
Form factorMicroUltra Small
CPU optionsIntel Gen6 i3/i5/i7Intel Gen2 i3/i5/i7; Celeron; Pentium;
ChipsetQ170Q65
Dedicated GPU *N.A.N.A.
RAMSODIMM DDR4-2133DIMM DDR3-1333
RAM slots22
RAM speed2133 MT/s1333 MT/s
RAM max32 GB8 GB
USB ports(6x) USB-A 3.0(7x)USB-A 2.0;
Video ports Display Port 1.2; HDMI 1.4;DisplayPort 1.2; VGA;
Other portsRJ45; Headset; Line-Out; RJ45; Hdph; (2x) Mic; Line-Out; Line-In; PS2/COM; Serial; Parallel;
Optional portsWiFi antenna; Display Port 1.2; VGA; Serial; Serial+PS2; N.A.
SATA ports12
PCI slotsN.A.N.A.
M.2 slotsM.2 2280 M-key (PCIe 3.0 x4, NVMe); M.2 2230 (WiFi/BT) N.A.
Drive bays2.5in2.5in; 5.25in(slim);
PSU65 W200 W
Weight1.41 kg (3.12 lb)3.27 kg (7.20 lb)
Released20152011
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 7040M and Dell OptiPlex 790 USFF

If you are looking for a more modern desktop, then you should go with the Dell OptiPlex 7040M which was released in 2015. The Dell OptiPlex 790 USFF is older and entered production in 2011.

If you are looking for the smaller form factor the Dell OptiPlex 7040M is the right one for you. It is smaller than the Dell OptiPlex 790 USFF 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 OptiPlex 7040M as it is running a newer generation CPU. This is not to say that Dell OptiPlex 790 USFF 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 OptiPlex 7040M is using the faster 2133 MT/s RAM. The Dell OptiPlex 790 USFF 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 OptiPlex 7040M as it has the ability to run 32 GB of RAM. The Dell OptiPlex 790 USFF 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 USFF has 7 USB ports. The Dell OptiPlex 7040M 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.

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.

The Dell OptiPlex 7040M comes with an HDMI port, while the Dell OptiPlex 790 USFF 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 USFF is better equipped as it comes with 2 SATA slot(s), while the Dell OptiPlex 7040M has 1 slot(s).

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 Dell OptiPlex 7040M. Sadly, the Dell OptiPlex 790 USFF 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 7040M comes with a decent 65 Watt PSU, but the Dell OptiPlex 790 USFF has a more powerful one rated at 200 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_7040M_motherboard.jpg motherboard layoutDell_OptiPlex_790_USFF_motherboard.jpg motherboard layout