Dell OptiPlex 3090 Tower vs. HP ProDesk 600 G3 Microtower
Comparison and Differences
Differences between Dell OptiPlex 3090 Tower and HP ProDesk 600 G3 Microtower
If you are looking for a more modern desktop, then you should go with the Dell OptiPlex 3090 Tower which was released in 2021. The HP ProDesk 600 G3 Microtower is older and entered production in 2017.
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 3090 Tower as it is running a newer generation CPU. This is not to say that HP ProDesk 600 G3 Microtower is bad - it can still run some powerful CPUs, albeit being an older generation.
Memory
The HP ProDesk 600 G3 Microtower has 4 RAM slots while the Dell OptiPlex 3090 Tower 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 Dell OptiPlex 3090 Tower is using the faster 2666 MT/s RAM. The HP ProDesk 600 G3 Microtower is slower by supporting RAM speeds of up to 2400 MT/s. In addition, you will be able to install the same amount of RAM in both models, and most probably 64 GB of RAM will be enough for most people. However, if you will be needing more RAM, make sure to check other desktop models too.
Ports
In total the HP ProDesk 600 G3 Microtower has 11 USB ports. The Dell OptiPlex 3090 Tower 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 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 600 G3 Microtower is better equipped as it comes with 5 SATA slot(s), while the Dell OptiPlex 3090 Tower 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 G3 Microtower comes with a decent 250 Watt PSU, but the Dell OptiPlex 3090 Tower has a more powerful one rated at 260 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.