It is also worth noting that one of your RISC corpses – and probably the most expensive failure – is Intel’s own Itanium.

You are right in general, of course – x86 are dominant in PC’s and servers. Much of this is due to Intel’s excellent engineering, and criminally good sales and marketing. But most of all it is due to software compatibility. And it is very much in spite of the hideous basic x86 architecture that was considered limited and outdated before the 8086 was first produced. The current Intel chips are proof that you can polish a turd.

What makes the big difference now compared to the Vax is software compatibility. For the past two decades, software has been dominated by pre-compiled binaries running on proprietary OS’s written for a single processor architecture. But these days hardware and software vendors are getting a lot more experience with cross-platform software that will run on different OS’s and different processors. The compatibility barrier is much lower – it is much easier to replace your x86 server with an ARM server if it runs the same web server, the same OS, the same file server, etc., as the old system.

System bus frequency : 333000000 Hz
CPU frequency : 499500000 Hz
DSP frequency : 333000000 Hz

True, ARM is more common, but I don’t know what CPU’s my Sony TV and Samsung Blu-ray player have, don’t have root access yet ;)

It is 64-bit and still low power, with more registers than the ARM and a similar orthogonal instruction set.

Now – *decades* later – we have a RISC architecture that could do to x86 what x86 did to the Vax? Maybe, but it will take more than just Android and iOS to make it happen. It will take an *Intel-sized* engineering, manufacturing and sales force to make it happen.

So might I expect before long (or already?) that there would be ARM motherboards offering serious multi-core CPU GHz and built-in powerful GPU, but really low electrical power consumption? And might I also expect a version of Ubuntu that runs all that.

Forgive any ignorant bits of the above.

For HPCs, ARMs will definitely be getting more popular. To get exascale there is little current alternative. Gpgpus are wanting for software, arm not so much. Also, convey has a chance to get a crack at things as well.