As far as I know RISC provides similar power efficiency and sleep that is like ARM.
ARM is Western
RISC is China / Eastern
Valve is just trying to outflank Microsoft here. And they're doing a magnificent job of it.
Microsoft has on at least half a dozen occasions tried to draw a box around Valve to control their attempts to grow beyond the platform. And moreover to keep gaming gravitas on Windows. Windows Store, ActiveX, Xbox, major acquisitions ... they've failed to stop Valve's moves almost every time.
Linux, Steam Box, Steam Machine - there's now incredible momentum with a huge community with more stickiness than almost any other platform. Microsoft is losing the war.
The ARM vs RISC battle will happen, but we're not there yet. There also isn't enough proliferation for it to be strategic to Valve.
RISC-V was developed at UC Berkeley. It's roughly as Western as West realistically gets, short of being made in Hawaii.
> That's a geopolitical question
Sure, but that's not actually about where RISC-V is from. It's that it's a purposely open platform -- so much so that its governing body literally moved to Switzerland.
The reason it's a geopolitical question is more to do with what we did to their supply chains with sanctions on companies like Huawei and ZTE, and what COVID did to everyone's supply chains independently of that. Both of those things made it really evident that some domestic supply chains are critical. (On both sides -- see: the CHIPS Act)
Where RISC-V comes back in is that open source doesn't really have a functioning concept of export restrictions. Which makes it an attractive contingency plan to develop further in the event of sanctions happening again, since these measures can and have extended to chip licenses.
(Edit: I'm not saying any of this is mutually exclusive with valid concerns about Huawei, raised by various other sources. I'm less familiar with ZTE's history, but my point in either case is more of a practical one.)