←back to thread

447 points stephenheron | 1 comments | | HN request time: 0s | 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

Show context
trashface ◴[] No.45019743[source]
I may be out of date or wrong, but I recall when the M1 came out there was some claims that x86 could never catch up, because there is an instruction decoding bottleneck (instructions are all variable size), which the M1 does not have, or can do in parallel. Because of that bottleneck x86 needs to use other tricks to get speed and those run hot.
replies(3): >>45020572 #>>45020647 #>>45022120 #
Remnant44 ◴[] No.45020647[source]
ARM instructions are fixed size, while x86 are variable. This makes a wide decoder fairly trivial for ARM, while it is complex and difficult for x86.

However, this doesn't really hold up as the cause for the difference. The Zen4/5 chips, for example, source the vast majority of their instructions out of their uOp trace cache, where the instructions have already been decoded. This also saves power - even on ARM, decoders take power.

People have been trying to figure out the "secret sauce" since the M chips have been introduced. In my opinion, it's a combination of:

1) The apple engineers did a superb job creating a well balanced architecture

2) Being close to their memory subsystem with lots of bandwidth and deep buffers so they can use it is great. For example, my old M2 Pro macbook has more than twice the memory bandwidth than the current best desktop CPU, the zen5 9950x. That's absurd, but here we are...

3) AMD and Intel heavily bias on the costly side of the watts vs performance curve. Even the compact zen cores are optimized more for area than wattage. I'm curious what a true low power zen core (akin to the apple e cores) would do.

replies(3): >>45021601 #>>45023366 #>>45023473 #
mycall ◴[] No.45021601[source]
When limited to 5 watts, the Ryzen HX 370 works pretty darn well. In some low-power user cases, my GPD Pocket 4 is more power efficient than my M3 MBA.
replies(3): >>45023002 #>>45023119 #>>45023250 #
aurareturn ◴[] No.45023002[source]
We are going to need to see some numbers for your claim. That’s not believable.
replies(1): >>45023169 #
ZiiS ◴[] No.45023169{3}[source]
A 8.8" screen takes a lot less power.
replies(1): >>45023215 #
aurareturn ◴[] No.45023215{4}[source]
When you say efficiency, I assume you’re factoring in performance of the device as well?

Maybe run Geekbench 6 and see.

replies(1): >>45025063 #
ZiiS ◴[] No.45025063{5}[source]
I am not the original commenter; but they said "low-power user cases" i.e. very much not when running Geekbench; rather when it is near idle.
replies(2): >>45025167 #>>45087829 #
1. aurareturn ◴[] No.45025167{6}[source]
FYI, AMD chips are notoriously bad at idle.