ARM rules the world

20 January 2011

The ARM processor architecture has dominated the mobile space for quite a long time. This is primarily because of the much better power performance of the chip. This drives battery size and thus overall weight and size of the device. So the recent announcement from Microsoft to start supporting ARM based computers is quite significant I think.

Firstly the announcement and the move by Microsoft is way too late, and feels like they have been forced into this rather than enthusiastic embracing of ARM. This will tell in the development and deployment of support. They will get it working, but they wont do much to make it work really well. The majority of windows installs will still be on Intel x86 chips for a very long time.

The growth in CPU Power will have to come from parallelism not faster chips. This is illustrated by developments in supercomputers and the quest for the 1000 core chip. A complex CPU, like the x86 will not scale well when we get to this level of cores. There just isn’t space to do this, let alone try and keep the CPUs cool.

The different approach that the ARM instruction set has is to be much smaller and rely on the compiler to perform optimisation rather build these into the silicon. This has been necessary for Intel to maintain backwards compatibility of the x86 family. Whereas the x86 chips have complex look ahead logic to detect loops and branches, in the ARM the compiler encodes these into the machine language.

I was speculating that if Microsoft got a solution together a new wave of netbooks and laptops running ARM chips would come available. Just imagine a netbook that had a 10 hour battery, that you could easily use all day without any power and recharge at night.

This is what the Google Chrome OS should deliver, but if OEMs could sell these with some sort of Windows on them there would be many available on the market so we could run our favourite Linux distribution on them.