Dell OptiPlex 3090 SFF vs. HP ProDesk 400 G3 Microtower
Comparison and Differences
Differences between Dell OptiPlex 3090 SFF and HP ProDesk 400 G3 Microtower
If you are looking for a more modern desktop, then you should go with the Dell OptiPlex 3090 SFF which was released in 2021. The HP ProDesk 400 G3 Microtower is older and entered production in 2015.
If you are looking for the smaller form factor the Dell OptiPlex 3090 SFF is the right one for you. It is smaller than the HP ProDesk 400 G3 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 Dell OptiPlex 3090 SFF as it is running a newer generation CPU. This is not to say that HP ProDesk 400 G3 Microtower 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 3090 SFF is using the faster 2666 MT/s RAM. The HP ProDesk 400 G3 Microtower is slower by supporting RAM speeds of up to 2133 MT/s. Additionally, if you will be needing a lot of RAM, better go for the Dell OptiPlex 3090 SFF as it has the ability to run 64 GB of RAM. The HP ProDesk 400 G3 Microtower can do a bit less at max 32 GB. Most of the times, this should be sufficient for the majority of users.
Ports
Both models have the same amount of USB ports for total count of 8. 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 Dell OptiPlex 3090 SFF comes with 2 ports, while the HP ProDesk 400 G3 Microtower has only 1. If you are planning to use multiple monitors, the Dell OptiPlex 3090 SFF 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 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 HP ProDesk 400 G3 Microtower is better equipped as it comes with 3 SATA slot(s), while the Dell OptiPlex 3090 SFF has 2 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 3090 SFF. Sadly, the HP ProDesk 400 G3 Microtower 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 3090 SFF comes with a decent 200 Watt PSU, but the HP ProDesk 400 G3 Microtower has a more powerful one rated at 300 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
