why was the M1 chip so revolutionary? What did it do that combined power with efficiency so well that couldn’t be done before?

Question

I ask this because when M1 Mac’s came I felt we were entering a new era of portable PCs: fast, lightweight and with a long awaited good battery life.

I just saw the announcement of the Snapdragon X Plus, which is looking like a response to the M chips, and I am seeing a lot of buzz around it, so I ask: what is so special about it?

In: Technology

Answer 1

It’s been technically possible for a long time but x86 was pretty entrenched for a long time. Everyone was sort of afraid breaking stuff and you sort of just needed someone with enough balls to do it that wasn’t afraid to create a paradigm shift. The biggest ace Apple had in its sleeve was Rosetta 2, which was not only very well done, but made it a far less painful transition. Arguably, that was the most revolutionary part of all.

As for what Apple did to get it so fast, they had a few things going on. ARM is a much cleaner instruction set than x86. There isn’t always a clear winner between CISC and RISC, and if we had a crystal ball and could start over you could create a good CISC instruction set that is more power efficient and generates less heat, but x86 is a large, old, crufty spec. Jim Keller (architect for a bunch of AMD and Intel processors) talked about this recently. Modern CISC uses micro instructions that are very RISC-like, and so a lot of modern speed gains in CPU design come from bringing things closer to the CPU and things like prediction. One argument in favour of RISC still possibly is that it’s a simpler instruction set to implement — I’m not a computer engineer but I imagine that’s a lot easier to reason about and iterate on when designing a chip.

Another thing was building a bunch of stuff on a single chip, which manufacturers have been doing for a while, but Apple took it a step further. Memory and graphics are tightly integrated onto the same package as the CPU, and the memory between CPU and GPU are unified.

One downside of this kind of design though is it might have major implications for the more open and modular PC designs of the past. There are a lot of people that like that they can upgrade and customize their hardware in a modular way, and these kinds of chip designs don’t allow for that so much.