I don't think there's anything specifically different about the reorder buffer between x86 and ARM. The reorder buffer size is just a logical consequence of th

I don't think there's anything specifically different about the reorder buffer between x86 and ARM. The reorder buffer size is just a logical consequence of the frontend width. And yes, scaling an Aarch64 frontend is dead simple compared to x86 due to the fixed instruction width. The disadvantage of x86 is serious, but I don't know if we can count it out quite yet. This is the first time Intel and AMD got any serious pressure on that front. I'm sure they're taking the challenge seriously, and it'll take some years before we'll see the results.