Hum, on the other hand patents up to Pentium 4 should have expired, right ? So, you might not be able to have "modern" CPU, depending on your definition of modern, but yet be abble to build specialized CPU with decent performance I suppose.
Right, did not thought of those. But they will not necessarily apply to a specialized embedded CPU. But, granted, a CPU for PC platform is a different story.
They might have some, but licensing from ARM gives you all in one neat package, and I’m not sure how much more economical it is to invest in RISC-V especially if you are smaller than WD.
WD is still pretty darn huge and that is kinda the point, with ARM you can roll out cores cheaply without worrying about needing additional licenses.
Until RISC-V will have an ecosystem of oven ready cores that can be licensed for essentially immediate tape out I’m not seeing it as a major threat to ARM.
The biggest threat so far seems to be that ARM may have to lower its fees even further at least for its embedded cores as there aren’t any RISC-V designs out there that threaten their Application Processor uArch yet.
The HiFive Unmatched board with quad U74 cores is available to order now on Mouser or CrowdSupply, with Mouser saying they'll have stock on Jan 1.
The U74 is very similar to an A55 without NEON.
I suspect SiFive is probably going to put the FU-740 SoC itself on Mouser once they have sufficient supplies to fulfill board orders.
Their U84 core was announced 12 months ago and is A72-equivalent (again excluding NEON). They way these things work there will probably be chips and boards available in another 12 months.
The VIU75 core was also just announced as available for licensing. That's a U74 plus RISC-V Vector extension (more like SVE than NEON).
Obviously ARM has already moved on from the A72 and they're up to A78 now with I think the A76 the latest actually shipping in devices (e.g. Samsung Galaxy S20). But RISC-V is catching up pretty quickly considering that four years ago there was no RISC-V chips shipping at all.
Also A72 to A78 is just incremental improvements, much like Nehalem to Sandy Bridge to SkyLake in x86. Of course the newer ones are better, but there are plenty of people out there still happily using Sandy Bridge.
In addition to that Esperanto is working on a 7nm based high performance AI product. However, they will also license the cores in that, including a high performance application core. That core should be on the upper end of available ARM cores.
