Dell OptiPlex 790 SFF vs. HP ProDesk 400 G5 Microtower
Comparison and Differences
Differences between Dell OptiPlex 790 SFF and HP ProDesk 400 G5 Microtower
If you are looking for a more modern desktop, then you should go with the HP ProDesk 400 G5 Microtower which was released in 2018. The Dell OptiPlex 790 SFF is older and entered production in 2011.
If you are looking for the smaller form factor the Dell OptiPlex 790 SFF is the right one for you. It is smaller than the HP ProDesk 400 G5 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 G5 Microtower as it is running a newer generation CPU. This is not to say that Dell OptiPlex 790 SFF is bad - it can still run some powerful CPUs, albeit being an older generation.
Memory
The Dell OptiPlex 790 SFF has 4 RAM slots while the HP ProDesk 400 G5 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 G5 Microtower is using the faster 2666 MT/s RAM. The Dell OptiPlex 790 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 HP ProDesk 400 G5 Microtower as it has the ability to run 32 GB of RAM. The Dell OptiPlex 790 SFF can do a bit less at max 16 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 HP ProDesk 400 G5 Microtower 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.
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 G5 Microtower. Sadly, the Dell OptiPlex 790 SFF 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 790 SFF comes with a decent 240 Watt PSU, but the HP ProDesk 400 G5 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
