Ah, Cortex ... Cortex is the branding for the ARM implementations of the ARM v7 Architecture. A brand was chosen for the first time because historically, even

Ah, Cortex ... Cortex is the branding for the ARM implementations of the ARM v7 Architecture. A brand was chosen for the first time because historically, even numbered ARM cores don't sell well (ARM8, anyone? ARM10?), so the next core after the ARM11 would have had to skip to ARM13. But 13 is unlucky. So that's ARM15 then... In addition, it would be very easy for the ARM v7 architecture to be confusd with the ARM7TDMI implementation of the ARM v4 architecture. The grand plan was to bring out new cores in V7 targetting three distinct market segments - Applications, Realtime and Microcontrollers (see what they did there?!), with very different performance points and feature sets. Thus, the Cortex M3 has a die size of 0.86mm2 on a 180nm process, but that's a weedy core. The A8 has a die size of a bit under 4mm2 on a 65nm (albeit speed optimised) process, without the ETM included. So, I'm not quite sure what core you are talking about - but it is also the case that the Atom die does contain a significant number of perhiperals and busses. A 64-bit ARM won't have a problem beating an x64 processor in terms of MIPS/Watt, I'm fairly sure. Edit - I should have explained that the number following the A/R/M is meant to indicate performance and not be a version number. The A5 and A9 both came out after the A8, for example - the ARM market isn't about increasing performance with every design, but ensuring a good fit for a design envelope.