Dell OptiPlex 3060 MT vs. HP ProDesk 490 G3 Microtower
Comparison and Differences
Differences between Dell OptiPlex 3060 MT and HP ProDesk 490 G3 Microtower
If you are looking for a more modern desktop, then you should go with the Dell OptiPlex 3060 MT which was released in 2018. The HP ProDesk 490 G3 Microtower is older and entered production in 2015.
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 3060 MT as it is running a newer generation CPU. This is not to say that HP ProDesk 490 G3 Microtower is bad - it can still run some powerful CPUs, albeit being an older generation.
Memory
The HP ProDesk 490 G3 Microtower has 4 RAM slots while the Dell OptiPlex 3060 MT 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 3060 MT is using the faster 2666 MT/s RAM. The HP ProDesk 490 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 HP ProDesk 490 G3 Microtower as it has the ability to run 64 GB of RAM. The Dell OptiPlex 3060 MT 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.
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.
The Dell OptiPlex 3060 MT comes with an HDMI port, while the HP ProDesk 490 G3 Microtower does not support the interface. Of course missing HDMI port is something that can be easily fixed with a good adapter (e.g. DisplayPort to HDMI).
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 Dell OptiPlex 3060 MT. Sadly, the HP ProDesk 490 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 3060 MT comes with a decent 260 Watt PSU, but the HP ProDesk 490 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.