Lenovo ThinkCentre M90n-IoT Internal
The bottom cover is secured with two screws, and then it slides off. This is very easy to service and you can see the cover being removed in the accompanying video.
On the left side of the PCB, we get a large thermal pad for the Samsung NVMe SSD. We can also see a Realtek RTL8111 NIC just below that area and above the red/black wire.
This system has a feature many may not expect in that it has a second M.2 mounting point for a second SSD. This is a PCIe Gen3 x2 slot for NVMe SSDs or a M.2 SATA slot adding a nice bit of extra expandability.
We can also see the Intel 9560NGW 802.11ac and Bluetooth 5.1 card that provides wireless access. Technically, this unit has three NICs, two wired, and one wireless.
On the other end of the unit, we get some interesting components next to the M.2 SSD. One can see a large hole in the motherboard PCB. In the non-IoT version there is a fan here, but in this passively cooled system that is omitted.
Perhaps the biggest feature is that we get a M.2 slot that is labeled “LTE” and WWAN. This is a slot designed to house a LTE card for wireless WAN access. Just above that slot, we see the SIM card slot. This unpopulated set of WWAN slots is next to the side ports that are meant to house antennas on the side of this chassis.
Perhaps the biggest negative is that the system does not have a strong CPU. This system comes with an ultra-low-power Intel Core i3-8145U. This is a dual-core, four-thread processor. Lenovo had to go with a low power option to passively cool the system.
Another major downside to the platform is the RAM. There is only a total of 4GB of memory in this system. That memory is not in a standard SODIMM slot. Instead, it is soldered onto the motherboard making easy upgrades effectively impossible. This is perhaps the biggest shortcoming of this system over a TinyMiniMicro node. If it had even a single SODIMM slot where memory could be installed, that would make a big difference. It is also a primary reason why this and the M90n Nano (non-IoT) we do not recommend as virtualization nodes except in very limited use cases. Project TinyMiniMicro nodes have faster CPUs and the capacity to get to higher RAM levels making them usually the better solution unless fanless operation and space are the primary drivers.
One benefit of this is ultra-low power consumption. At idle, this unit rivals the BMCs found on many Atom-based server motherboards when the server is powered off. As a trade-off, we do not get IPMI access.
Use Cases: The Good and Bad
First, the addition of COM ports means that this has a market. The Project TinyMiniMicro nodes often have COM ports, but this is a lower-power fan-less option if you just need serial ports for data collection/ processing or even just to serve as console access to devices. A great use case is ingesting data from a sensor and parsing/ compressing logs directly on this device to limit the amount of data that needs to be uploaded.
The dual 1GbE NICs also make this potentially suitable as a firewall appliance. While there are less expensive options on the market using Atom chips, this has a higher-end CPU and is also sold by Lenovo with an on-site warranty. These are Realtek NICs, but we get asked about dual NICs in the Project TInyMiniMicro segment, so we think it is an important point.
The second SSD slot adds some functionality, but this is probably not the ideal NAS solution. Likewise, as a desktop, having the included Windows 10 Home license is great, but it is a slow dual-core processor with 4GB of memory so it is far from an ideal modern desktop experience. Our sense is that most will use this as an IoT node instead of as a primary desktop.
The appeal of this unit is clearly the passive chassis and relatively solid set of features. We can forgive many of the shortcomings of the system due to this design, along with the price.
In a few of these photos, as well as in the video, you will see we had the non-IoT Lenovo M90n Nano. To us, that is a better desktop experience, but the use cases as a server node are a bit harder for us to justify. Unless space is at an extreme premium, moving up to the Project TinyMiniMicro 1L form factor makes a lot of sense since one can effectively have nodes that have 2-8x the CPU performance and memory capacity (our non-IoT version has 8GB of memory.) Effectively, one needs a cluster of the non-IoT Nanos to equal a TinyMiniMicro 1L node making the TMM nodes a much better fit unless there is an extremely narrow use case.
Overall, this is an interesting little system that is frankly made more interesting based on the pricing. At $800 this would be a tough sell. At $419 when we reviewed the 256GB version last year, it was a decent option. At $200 new from Lenovo, this appeals to a completely new set of users. Hopefully, that was not just an end-of-year deal.
We have gotten many questions on this and the non-IoT version as part of our TinyMiniMicro series. We generally consider these as a different segment due to different feature sets and limitations of the smaller form factors. We hope this piece both answers some of those questions while providing a view of the segment from a TinyMiniMicro perspective.