I still wonder how Apple was able to achieve such an incredible performance per watt ratio compared to Intel and AMD. Anybody knows how they let Apple do it?
1. Arm is generally more efficient than x86. 2. Apple uses TSMC's latest nodes before anyone else. 3. Apple doesn't chase peak performance like AMD and Intel. CPU speed and power consumption is not linear. Intel has been chasing 5GHZ+ speeds the last few years which consumes considerably more power. Apple keeps their CPUs under 3.5GHZ.
This is not entirely true in general sense. Yes, a typical ARM CPU is more energy efficient indeed, but theoretically nothing prevents x86 to be nearly as efficient.
The main reason why Apple silicon is more efficient is that Apple silicon is a mobile chip basically, and competition on mobile is harsh, so all the producers had to optimize their chips a lot for energy efficiency.
On the other hand until apple silicon and recent AMD ascension there was a monopoly of Intel on a laptop market with no incentive to do something. Just look at how fast Intel developed asymmetric Arm-like P/N-core architecture right after Apple Silicon emerged. Let's hope this new competitor will force more energy efficient x86 chips to be produced by intel and amd eventually.
The very complex instruction set does. You can easily throw multiple decoders at Arm code, but x86 scales badly due to the variable length. Current cores need predecoders to find instruction boundaries which is just not needed with fixed width instructions and even then can only decode simpler instructions with the higher numbered decoders.
i.e., PSPACE ⊆ EXPTIME
https://en.wikipedia.org/wiki/EXPTIME
which is funny because people are always like "uh why do i need to understand asymptotics when machines are so fast". well the answer is the asymptotics catch up to you when the speed of light isn't infinite or when you're timing things down to the nanosecond.
The question is, how much overhead does it cause compared to the whole picture. There are empirical evidences the answer is "very little":
https://chipsandcheese.com/2021/07/13/arm-or-x86-isa-doesnt-...
> With the op cache disabled via an undocumented MSR, we found that Zen 2’s fetch and decode path consumes around 4-10% more core power, or 0.5-6% more package power than the op cache path. In practice, the decoders will consume an even lower fraction of core or package power.
Intel and AMD also make low-power parts.
You can't compare a chip running at 3ghz with one running at 5ghz. It just doesn'tell you anything useful about the architecture, only what the company configuring the chip thought mattered.
Being "only" 30% faster but using twice the power at 5ghz, for example, is entirely expected. Chances are the M1 couldnt even run that fast, or it would end up using just as much power if it did.
* Within up to 15% at 25W.
Maybe in light threads that utilize many cores.
Most reviewers base it on Cinebench which is a poor indication of CPU performance for anything except Cinemark. Cinebench uses Intel Embree Engine which is hand optimized for x86. In addition, Cinebench favors CPUs with many slow cores - which is not how most software will perform. This is why AMD heavily marketed Cinebench for Zen1 launch and why Intel heavily markets it now for Alder Lake/Raptor Lake. In fact, Intel's little cores are basically designed to win at Cinebench.
Furthermore, AMD CPUs will rate at 25w but can easily boost up to 40w+ watts. It's up to the laptop maker.
Not sure what you mean by many slow cores, since mobile zen 4 has a better single-core performance than m2 pro.
Zen4 mobile does not have higher ST performance than M2 series.
https://browser.geekbench.com/processors/amd-ryzen-7-pro-784...
https://browser.geekbench.com/macs/mac-mini-2023-12c-cpu
7840u's ST is slower by 21% while consuming much more power during the test.
What do you mean “how they let Apple do it”. Do you think Intel & AMD could stop them?
https://www.reddit.com/r/castles/comments/4t5w0q/round_vs_sq...
PCs have been stuck to 3/4Ghz for more than 15 years, so it is not like they didn't have the time to optimize from the consumption/heat point of view.
For a while Intel's process knowledge was supposed to be better, even if the design was less efficient, but that turned out to be a mirage around 10nm or so. Intel now without a process advantage is probably never going to regain it's monopoly, and so far hasn't really transformed itself to do anything other than build those high-margin chips.
Once upon a time, I wanted to use one of the chips from a company they bought in networking, but Intel's model is to make the chip and let other companies make a product to take it to market. Intel doesn't want to make a market, just sell into it. You can see that with their attempt at TV where they stopped when they didn't want to spend money on content. So the chip I was interested in didn't get much R&D or a product and it more or less disappeared, another wasted investment.