Released earlier this week, the Surface Pro X is Microsoft's first Windows on ARM PC, after its partners released two generations of it using the Snapdragon 835 and Snapdragon 850. But now, we're in the era of the Snapdragon 8cx, a Qualcomm chipset that's built from the ground up for PCs and is meant to be on par with an Intel Core i5.
This one uses a custom chip, the Microsoft SQ1. The SQ1 still has some mystery around its specs, but it's pretty much an overclocked 8cx with a slightly different GPU. The 'SQ' stands for Surface Qualcomm, as Microsoft and Qualcomm worked together on this, just like with the 8cx. It's meant to have some optimizations in it for the Surface Pro X.