Booting Windows from microSD card on the STK2M3W64CC

Whilst the latest Intel Core M Compute Stick comes pre-loaded with Windows 10 it is possible to dual-boot. This is typically achieved by reducing the partition space allocated to Windows and creating a new partition for Ubuntu or similar. The assumption has always been that the faster eMMC storage would be reserved for the OS and any additional data storage could be gained from using either a USB or a microSD card or both.

But what if the eMMC storage is totally dedicated to the primary OS and the secondary OS runs from the supplementary storage? Again this approach has been successfully with booting Ubuntu installed on a USB or a microSD card thereby leaving Windows untouched on the 'disk'.

However for some the requirement is for Ubuntu to be the primary OS and Windows the secondary one. There would obviously be no problem in installing and running Ubuntu but what doesn't seem to have discussed previously is whether it is possible to run Windows from the microSD card and what the performance is like.

Because the Windows 10 license key is now embedded in the BIOS and also because Microsoft allows the installation (or re-installation) of Windows 10 using a USB the creation of a bootable Windows microSD card is very simple. And if a fast enough microSD card is used then the performance is actually quite acceptable.

To demonstrate this I've used a Sandisk Extreme Pro microSD card. After installation to the microSD card Windows both automatically activates and boots by default:

First looking at the I/O performance:

the biggest issue is the 'write' speed as this is substantially slowed than for eMMC.

But this won't adversely affect everything. Taking a look at the graphics performance using the 3D Mark tests we see very similar results to those obtained when running the default Windows configuration:

and interestingly there is a slight improvement for PC Mark 8 Home (accelerated):

It only really becomes apparent in Passmark's benchmark where disk performance is a significant factor in the overall rating :

However JavaScript still performs well:

To choose whether to boot Ubuntu or Windows an NVRAM option needs to be added for Ubuntu and GRUB reconfigured. Here's a video demonstrating booting:

https://youtu.be/8kj6dijx4Xs

Overall the performance is perfectly acceptable for a secondary OS and certainly a workable configuration.