[rbanffy]

> f it's known that arm outperforms x86 while also being more power efficient, why aren't everyone using it?

PowerPC and Alpha did that in the 90's and the reason is software.

Intel's x86 has a huge software ecosystem. In 1999 (thanks to a procurement mistake) I was reading my e-mail and browsing documentation on a wicked fast 64-bit computer. It would be a good couple more years before I could edit a Word document on a 64-bit computer because Microsoft didn't have Office for them. I only got to read e-mail on that ridiculously fast Unix workstation because nobody wanted to use it and it was just sitting there running our timesheet software and magnificent screensavers.

Multi-processor x86 desktop machines only became popular when Windows XP became popular. Multi-processor Macs only became popular when Apple moved to OSX. IBM only added multi-processor support for their mainframes when they hit a dead end and had to move to machines with slower CMOS processors with more processors to make up for the speed they lost.

Software dynamics holds hardware evolution back.