> > According to Feldman an entirely custom server chip using the ARM architecture takes about 18 months
> > and about $30 million. By contrast, it takes three or four-year time frame and $300--400 million in
> > development costs required to build an x86-based server chip based on a new micro-architecture.
>
> An interesting video confirms what you are saying. Search for: Jim
> Keller On AMD's Next-Gen High Performance x86 & K12 ARM Cores.
>
> Saw this couple of months, but if my memory serves me correctly, he said that with the
> same transistor budget he is able to build a faster core with Aarch64 than with x86_64.
> Time will tell if that is true, but Jim seems to know what he is talking about.

Jim is 100% right - it is a bit easier to design an ARMv8 core than x86, all things being equal. How much is the difference though?

I wrote about this extensively before:

http://www.realworldtech.com/microservers/4/

My analysis is as follows: assume a 15% gain for an ARM core vs. x86 (I think 5-10% is more realistic, but let's be generous), that is only a 5% gain at the chip level. 5% just isn't a significant advantage.

David