ARM CPUs and Windows 8 – What Does it Mean?

It’s no secret now that Windows 8 is going to be compatible with ARM CPUs. This is an interesting move as the general belief in the technical ranks was that Microsoft would scale up Windows Phone to the tablet form factor rather than have another tilt at shoehorning its desktop operating system into low powered tablets (an approach that hasn’t worked tremendously well in the past).

One thing that has been in common across tablets from the Windows 95, XP and Vista eras is the x86 CPU (more often than not designed by Intel). Over time, these CPUs have had more and more instructions packed into them and, in most cases, successive generations of CPUs have possessed a superset of instruction sets compared to prior generations (things like MMX, SSE, SSE2, etc). Unfortunately, what this also means is while a CPU is powered up all of those extra bits of silicon are chewing up power even when they are not in use.

This is exactly what you don’t want in mobile or portable devices when battery life is a big deal.

The benefit of ARM CPUs is that they can be tailored to provide only the specific instructions required for the purpose in which they will be used. For instance, it makes no sense to include video decoding instructions in a CPU when it is only going to be used in a network router.

ARM CPUs can be found in portable consoles such as the Nintendo 3DS/DS, smartphones such as the Samsung Galaxy S and Apple iPhone, and digital SLR cameras like the Cnanon EOS 5D Mark II. These CPUs very much have the stranglehold in the mobile space and have proven to provide the best . Intel has attempted to compete in this space with its XScale CPUs which appeared in heaps of old Windows Mobile devices last decade but never gained a foothold. In terms of the low end computer market (i.e. netbooks), Intel has produce incredibly stripped down CPUs like the Intel Atom that do enough to run a computer with minimal performance. Unfortunately for Intel, Microsoft’s inclusion of ARM CPUs could make the use of lower end x86 CPUs like the Atom a poor choice and give ARM CPUs even more penetration into the market.

I guess we will see what sort of impact this move by Microsoft will have on the industry and Intel as time progresses. A Windows tablet might just give Android and iOS a run for their money.