Dell Vostro 3902 vs. HP ProDesk 400 G2 Microtower
Comparison and Differences
Differences between Dell Vostro 3902 and HP ProDesk 400 G2 Microtower
Both computers, the Dell Vostro 3902 and the HP ProDesk 400 G2 Microtower, were released during the same year - 2014.
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 HP ProDesk 400 G2 Microtower as it is running a newer generation CPU. This is not to say that Dell Vostro 3902 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.
None of the desktops has an advantage when it comes to the speed of the RAM being used. Both models support RAM speeds of up to 1600. In addition, you will be able to install the same amount of RAM in both models, and most probably 16 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 Dell Vostro 3902 has 8 USB ports. The HP ProDesk 400 G2 Microtower is inferior in this regard and packs 6 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.
Nowadays, almost every new computer comes equipped with a DisplayPort. However, none of the devices being compared here has one. Don't worry though, DisplayPort adapters are very cheap and you can get virtually any combination of conversion types.
The Dell Vostro 3902 comes with an HDMI port, while the HP ProDesk 400 G2 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 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 Vostro 3902 is better equipped as it comes with 4 SATA slot(s), while the HP ProDesk 400 G2 Microtower has 3 slot(s).
M.2 SSD interface allows you to transfer data with higher speeds compared to the old SATA interface. Unfortunately, neither the Dell Vostro 3902, nor the HP ProDesk 400 G2 Microtower has one. However, you can still use a SATA SSD drive which should give you satisfactory performance.
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
Looking at the Power Supply Unit (PSU) of the two models we don't see any differences. For either of them you get a maximum power of 300 Watts. However be careful, many models have more than one power supply option. When buying your computer, it is a good idea to get a version with the most powerful PSU. This will potentially allow you to upgrade to a more powerful GPU for example.
Motherboard
