Dell OptiPlex 7070 SFF vs. Lenovo ThinkCentre M900 Tower
Comparison and Differences
Differences between Dell OptiPlex 7070 SFF and Lenovo ThinkCentre M900 Tower
If you are looking for the smaller form factor the Dell OptiPlex 7070 SFF is the right one for you. It is smaller than the Lenovo ThinkCentre M900 Tower and will fit more easily under your desk.
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 7070 SFF as it is running a newer generation CPU. This is not to say that Lenovo ThinkCentre M900 Tower is bad - it can still run some powerful CPUs, albeit being an older generation.
Both models have have equal amount of ram slots (4 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.
The Dell OptiPlex 7070 SFF is using the faster 2666 MT/s RAM. The Lenovo ThinkCentre M900 Tower is slower by supporting RAM speeds of up to 2133 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.
In total the Dell OptiPlex 7070 SFF has 10 USB ports. The Lenovo ThinkCentre M900 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. What is nice about the Dell OptiPlex 7070 SFF, is that it has 1 USB 3.1 port(s) which allows transfer of up to 10Gb/s. Unfortunately, the Lenovo ThinkCentre M900 Tower has no such port, thus restricting your transfer speeds significantly. For people who want to use external drives on regular basis, this might be an issue.
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 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 7070 SFF. Sadly, the Lenovo ThinkCentre M900 Tower 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!
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 7070 SFF comes with a decent 200 Watt PSU, but the Lenovo ThinkCentre M900 Tower has a more powerful one rated at 400 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.