Dell OptiPlex 390 DT vs. Lenovo ThinkCentre M800 Tower
Comparison and Differences
Differences between Dell OptiPlex 390 DT and Lenovo ThinkCentre M800 Tower
If you are looking for a more modern desktop, then you should go with the Lenovo ThinkCentre M800 Tower which was released in 2015. The Dell OptiPlex 390 DT is older and entered production in 2011.
If you are looking for the smaller form factor the Dell OptiPlex 390 DT is the right one for you. It is smaller than the Lenovo ThinkCentre M800 Tower 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 Lenovo ThinkCentre M800 Tower as it is running a newer generation CPU. This is not to say that Dell OptiPlex 390 DT is bad - it can still run some powerful CPUs, albeit being an older generation.
Memory
The Lenovo ThinkCentre M800 Tower has 4 RAM slots while the Dell OptiPlex 390 DT 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 Lenovo ThinkCentre M800 Tower is using the faster 2133 MT/s RAM. The Dell OptiPlex 390 DT is slower by supporting RAM speeds of up to 1333 MT/s. Additionally, if you will be needing a lot of RAM, better go for the Lenovo ThinkCentre M800 Tower as it has the ability to run 64 GB of RAM. The Dell OptiPlex 390 DT can do a bit less at max 8 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.
Unfortunately, only the Lenovo ThinkCentre M800 Tower has a DisplayPort. The Dell OptiPlex 390 DT does not have one? Don't worry though, nowadays video adapters are cheap and you can get almost any combination of conversion types.
The Dell OptiPlex 390 DT comes with an HDMI port, while the Lenovo ThinkCentre M800 Tower 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 OptiPlex 390 DT is better equipped as it comes with 4 SATA slot(s), while the Lenovo ThinkCentre M800 Tower 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 OptiPlex 390 DT, nor the Lenovo ThinkCentre M800 Tower 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 250 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
