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Ask HN: Why hasn't x86 caught up with Apple M series?

447 points stephenheron | 2 comments | 25 Aug 25 21:50 UTC | HN request time: 0.441s | source

Hi,

My daily workhorse is a M1 Pro that I purchased on release date, It has been one of the best tech purchases I have made, even now it really deals with anything I throw at it. My daily work load is regularly having a Android emulator, iOS simulator and a number of Dockers containers running simultaneously and I never hear the fans, battery life has taken a bit of a hit but it is still very respectable.

I wanted a new personal laptop, and I was debating between a MacBook Air or going for a Framework 13 with Linux. I wanted to lean into learning something new so went with the Framework and I must admit I am regretting it a bit.

The M1 was released back in 2020 and I bought the Ryzen AI 340 which is one of the newest 2025 chips from AMD, so AMD has 5 years of extra development and I had expected them to get close to the M1 in terms of battery efficiency and thermals.

The Ryzen is using a TSMC N4P process compared to the older N5 process, I managed to find a TSMC press release showing the performance/efficiency gains from the newer process: “When compared to N5, N4P offers users a reported +11% performance boost or a 22% reduction in power consumption. Beyond that, N4P can offer users a 6% increase in transistor density over N5”

I am sorely disappointed, using the Framework feels like using an older Intel based Mac. If I open too many tabs in Chrome I can feel the bottom of the laptop getting hot, open a YouTube video and the fans will often spin up.

Why haven’t AMD/Intel been able to catch up? Is x86 just not able to keep up with the ARM architecture? When can we expect a x86 laptop chip to match the M1 in efficiency/thermals?!

To be fair I haven’t tried Windows on the Framework yet it might be my Linux setup being inefficient.

Cheers, Stephen

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PaulKeeble ◴[26 Aug 25 05:47 UTC] No.45022719[source]▶
I tend to think its putting the memory on the package. Putting the memory on the package has given the M1 over 400GB/s which is a good 4x that on a usual dual channel x64 CPU and the latency is half that of going out to a DRAM slot. That is drastic and I remember when the northbrige was first folded into the CPU by AMD with the Athlon and it had a similarly big improvements in performance. It also reduces power consumption a lot.

The cost is flexibility and I think for now they don't want to move to fixed RAM configurations. The X3D approach from AMD gets a good bunch of the benefits by just putting lots of cache on board.

Apple got a lot of performance out of not a lot of watts.

One other possibility on power saving is the way Apple ramps the clockspeed. Its quite slow to increase from its 1Ghz idle to 3.2Ghz, about 100ms and it doesn't even start for 40ms. With tiny little bursts of activity like web browsing and such this slow transition likely saves a lot of power at a cost of absolute responsiveness.

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1. Tuna-Fish ◴[26 Aug 25 06:07 UTC] No.45022834[source]▶
> and the latency is half that of going out to a DRAM slot.

No, it's not. DRAM latency on Apple Silicon is significantly higher than on the desktop, mainly because they use LPDDR which has higher latencies.

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2. Remnant44 ◴[26 Aug 25 07:43 UTC] No.45023472[source]▶
I was going to mention this as well.

Source: chipsandcheese.com memory latency graphs