distantskeptic

Responding to my own post to add more detail...

Open source CPU design is fundamentally different than open source software design. In the latter costs are extremely low - just the cost of a computer per developer. That developer's computer need not be replaced for years. There is no significant incremental cost for a software bug - just recompile and in a few minutes you're off to the races with a new executable which can be distributed over the internet for next to nothing. Contrast that with CPU design - every time a hardware bug is found you'd have to fix the design, verify it in software simulations, fabricate a new wafer, package it, install it in test hardware, and then perform hardware verification. This is 5 to 6 orders of magnitude slower and more expensive than software. Sure, corporations can perform this open CPU design, verification and manufacturing function. But in the end for a CPU to have a certain level of speed and reliability, you'd have to spend at least the same amount of money as the commercial CPU makers. Companies that produce an open source CPU chip are incurring huge monetary risks - and would have to be compensated for this risk if their chips have bugs and cannot be sold.

The only way for an open source chip design to be remotely competitive would be if they were to embrace FPGA technology. But FPGAs run 4 times slower than purpose built ASICs and are at least 10 times more expensive per unit in volume.

I'm skeptical about RISC-V or any other open CPU design providing the quality of commercial designs. Testing and verification is not free. ARM tests their designs with millions of hours of simulation of heavy multithreaded workload, and chip implementors would have done the same with the actual silicon. Licensing costs of commercial ARM chips are a drop in the bucket compared to this necessary expense to ensure reliability.