Today, we are going to get into the Lenovo M75n IoT. This device is perhaps the lowest-performing device we have looked at as part of our look at potential edge servers, but it is also unique. Inside is a dual-core, four-thread AMD Zen-based CPU that runs at a paltry 6W. That means that the M75n IoT is not just low power, but also fanless. About ten months ago we looked at the Lenovo ThinkCentre M90n-IoT in a practical look at a device that William reviewed a year earlier. That is the higher-power Intel solution. There are certainly some significant tradeoffs, but let us get into them in what is more of a TinyMiniMicro style piece.
Lenovo ThinkCentre M75n IoT Background
We wanted to take a look at this system from a different perspective given the drastically changed pricing. We also have a video on this unit on the STH YouTube channel here:
As always, we suggest opening the video in a larger browser if you want to check out the video as that usually has a better viewing experience.
A bit of background on this. Both the M75n IoT and M75n have been out for some time. We originally ordered them through CDW, a large US reseller/ distributor, and the order was never filled. That was $202 used for the 8GB/ 256GB model, but again, it never shipped.
Some time passed, then we had the opportunity to get both at a very attractive price point. This IoT version, we managed to get for $188.
The configuration included an AMD Athlon Silver 3050e dual-core processor, 4GB of memory, and a 128GB SSD. We were a bit surprised that we also got a keyboard and mouse in the box. This was a similar configuration to the M90n IoT we looked at previously.
As a result, we wanted to take a look at the system as an alternative to our Project TinyMiniMicro series and just do a quick hardware/ application overview.
Lenovo ThinkCentre M75n IoT Overview
The Lenovo ThinkCentre M75n-IoT is a very compact chassis.
Just for some sense of size, it is considerably smaller than a Project TinyMiniMicro node such as the Lenovo ThinkCentre M920x. There are certainly trade-offs being made to achieve this small size. Here is the side-by-side with this chassis and a 1L PC:
One of the high points of this system is the connectivity. On the front, we get three USB ports. Two are Gen2 10Gbps ports including the Type-C and one Type-A. The middle Type-A port is a USB 2.0 port. Compared to the M90n IoT, this trades a USB 3.1 Gen2 10Gbps port for a USB 2.0 port on the M75n IoT, a major downgrade.
Unlike the desktop-focused Nano units, the IoT version adds two serial COM ports. These are important since there are many IoT devices that utilize serial interfaces. Another major benefit of the legacy interface is that one can screw the serial cable in to secure it which is more resistant to inadvertently coming loose. Modern USB ports are designed to disconnect mush more easily. There is also a headset port which is a nod to this being a semi-shared platform with the desktop nano. It is unlikely you would have this machine running factory robots while also providing headset duties for Zoom meetings. Still, we can see some use for it, and Lenovo likely thought it was a low cost so it remained.
The rear of the unit has a fairly standard power input (via a 65W power adapter) a display port and two additional USB 3.2 Gen2 10Gbps ports. One is a Type-A and one is a Type-C port. For a second display output, we do not have a standard DP/ HDMI port. Instead, Lenovo utilizes the Type-C port with an adapter to get a second video out from this unit.
Perhaps a big feature difference here between the M90n IoT and M75n IoT comes down to networking. On the M75n IoT unit, we have a single 1GbE port. One of the big asks we get around Project TinyMiniMicro nodes is around adding a second wired NIC. We even have a Guide to Turning a Project TinyMiniMicro Node into a pfSense Firewall due to requests around that solution. Here, we get a Realtek RTL8111/ RTL8111FP-CG -based NICs. For FreeBSD, we generally recommend updating drivers as sometimes the included drivers are dated and can cause performance issues. OSes such as Windows have more updated drivers. Still, for those thinking this may be a perfect firewall with a low-power AMD Zen offering, the single NIC feature is likely going to be offputting.
Both of these units have 802.11ac WiFi so we get an antenna header. We also get a Kensington lock port in the same location. These are nearly identical chassis with only some minor modifications.
You may have noticed a plastic cover in some of the photos, but not in others. This plastic cover is designed to add some protection from the top of the M75n-IoT’s heatsink. This is a passively cooled unit, so the system can get potentially warm.
Next, let us look inside the system and discuss applications.