Dell OptiPlex 790 DT vs. Lenovo ThinkCentre M800 Tower
Comparison and Differences
Differences between Dell OptiPlex 790 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 790 DT is older and entered production in 2011.
If you are looking for the smaller form factor the Dell OptiPlex 790 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 790 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 790 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 790 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 790 DT can do a bit less at max 16 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.
DisplayPort is crucial for any desktop machine. It is good to see that both models are featuring DisplayPorts. However, the Lenovo ThinkCentre M800 Tower comes with 2 ports, while the Dell OptiPlex 790 DT has only 1. If you are planning to use multiple monitors, the Lenovo ThinkCentre M800 Tower is the better choice.
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 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.
M.2 SSD interface allows you to transfer data with higher speeds compared to the old SATA interface. Unfortunately, neither the Dell OptiPlex 790 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
