Dell OptiPlex 5090 SFF vs. HP ProDesk 600 G4 SFF
Comparison and Differences
Differences between Dell OptiPlex 5090 SFF and HP ProDesk 600 G4 SFF
If you are looking for a more modern desktop, then you should go with the Dell OptiPlex 5090 SFF which was released in 2021. The HP ProDesk 600 G4 SFF is older and entered production in 2018.
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 OptiPlex 5090 SFF as it is running a newer generation CPU. This is not to say that HP ProDesk 600 G4 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 (4 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 5090 SFF is using the faster 3200 MT/s RAM. The HP ProDesk 600 G4 SFF is slower by supporting RAM speeds of up to 2666 MT/s. Additionally, if you will be needing a lot of RAM, better go for the Dell OptiPlex 5090 SFF as it has the ability to run 128 GB of RAM. The HP ProDesk 600 G4 SFF can do a bit less at max 64 GB. Most of the times, this should be sufficient for the majority of users.
Ports
In total the HP ProDesk 600 G4 SFF has 11 USB ports. The Dell OptiPlex 5090 SFF is inferior in this regard and packs 10 USB ports. In any case, if you miss USB ports, you can always purchase a USB hub. It's great that both of the models have USB 3.1 ports which will allow you to exchange data with your peripherals at up to 10Gb/s. But if you need maximum connectivity, go with the HP ProDesk 600 G4 SFF as it has 5 USB3.1 ports (the Dell OptiPlex 5090 SFF has 1).
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 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 5090 SFF is better equipped as it comes with 4 SATA slot(s), while the HP ProDesk 600 G4 SFF has 3 slot(s).
When your goal is to have the fastest SSD transfer speeds, an M.2 interface is crucial. Thus, it is good that both models have M.2 SSD slots. Today M.2 SSDs are not much more expensive than the average SATA drives, so it really does not make sense to invest in SATA drives anymore.
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 HP ProDesk 600 G4 SFF comes with a decent 180 Watt PSU, but the Dell OptiPlex 5090 SFF 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.