Dell OptiPlex 3020M vs. HP ProDesk 400 G5 Mini
Comparison and Differences
Differences between Dell OptiPlex 3020M and HP ProDesk 400 G5 Mini
Both models have the same form factor, meaning reoughtly they have the same phiysical size and form.
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 Mini as it is running a newer generation CPU. This is not to say that Dell OptiPlex 3020M is bad - it can still run some powerful CPUs, albeit being an older generation.
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 HP ProDesk 400 G5 Mini is using the faster 2666 MT/s RAM. The Dell OptiPlex 3020M is slower by supporting RAM speeds of up to 1600 MT/s. Additionally, if you will be needing a lot of RAM, better go for the HP ProDesk 400 G5 Mini as it has the ability to run 64 GB of RAM. The Dell OptiPlex 3020M can do a bit less at max 16 GB. Most of the times, this should be sufficient for the majority of users.
Both models have the same amount of USB ports for total count of 6. If this is not enough, using a USB hub is always a viable option. 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.
DisplayPort is crucial for any desktop machine. It is good to see that both models are featuring DisplayPorts. However, the HP ProDesk 400 G5 Mini comes with 2 ports, while the Dell OptiPlex 3020M has only 1. If you are planning to use multiple monitors, the HP ProDesk 400 G5 Mini is the better choice.
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 1 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 Mini. Sadly, the Dell OptiPlex 3020M 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!
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 3020M comes with a decent 65 Watt PSU, but the HP ProDesk 400 G5 Mini has a more powerful one rated at 150 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.