It's probably not RISC-V or Apple that worries ARM. It's probably Qualcomm. Qualcomm has been licensing ARM's core designs since the beginning of the smartphone

It's probably not RISC-V or Apple that worries ARM. It's probably Qualcomm. Qualcomm has been licensing ARM's core designs since the beginning of the smartphone era. Qualcomm bought Nuvia so that they could design their own cores and pay much lower royalties just for the instruction set. ARM has a lawsuit against Qualcomm/Nuvia because Nuvia's agreement with ARM was (allegedly) that they wouldn't sell their IP to anyone without ARM's approval. However, churning out cores that are better than what Qualcomm/Nuvia can produce would make non-Qualcomm processors faster or keep the money coming from Qualcomm. ARM doesn't need to catch up with Apple. Apple hasn't been buying ARM's designs for many years and there's no chance that will change. Even if Apple is faster, the whole Android world needs ARM's designs and most customers aren't choosing iPhones because Apple has faster processors. Apple's no threat to ARM in the data center since Apple isn't interested in the market. ARM probably isn't that afraid of RISC-V at this point. Yes, there are some companies doing good things with RISC-V, but you don't have to look far to see how hard it is to create a great processor. Qualcomm has way more resources than RISC-V startups and they bought Nuvia (with engineers who made Apple Silicon) and they still aren't pushing their own cores. When you look at software benchmarks on ARM, there's often some lag (compared to x64) due to less mature compiler optimization and that's going to be even worse for RISC-V. While a lot of software is portable, it's not a drop-in replacement. A lot of Linux distros aren't even supporting ARM that well at the moment. None of this is meant to belittle RISC-V. It's simply meant to note that there's a big hill to climb and it takes a long time to climb that hill. Even Apple who control their whole ecosystem took a very long time. Apple started shipping their own designs in 2010 and it was a decade before they made their way into MacBooks. Apple has the kind of money and ecosystem control that make such a move easier. That's not to say that RISC-V can't make a big impact, but rather to note that the threat from RISC-V is probably significantly farther out. There are always threats, but the big threat right now is Qualcomm (and others) moving away from ARM's designs. If they're able to just pay instruction set licenses instead of the core licenses, it'll dry up ARM's revenue. As ARM's revenue dries up, they won't have the money to invest in new core designs. That will accelerate the decline of ARM's revenue as it becomes easier to beat their core designs.