16-inch MBP 2x slower than M1 MacBook Air in a real-world Rust compile

Re:16-inch MBP 2x slower than M1 MacBook Air in a real-world... by throwaway894345 on Tuesday November 17, 2020 @01:39PM (#25127730)

I’m guessing the performance improvements derive from integrating the memory onto the same chip (instead of using external memory), not from ARM (although power savings come from ARM). So we will probably see a new era of laptop SoCs, but that also means coupling RAM with CPU (or maybe you can mix and match the on-chip RAM with external RAM?).

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Re:16-inch MBP 2x slower than M1 MacBook Air in a real-world... by wmf on Tuesday November 17, 2020 @01:42PM (#25127775)

I’m guessing the performance improvements derive from integrating the memory onto the same chip

Nope, LPDDR4x-4266 is LPDDR4x-4266. Apple, Intel, and AMD all have access to the same RAM. The Firestorm core is the real advantage.

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Re:16-inch MBP 2x slower than M1 MacBook Air in a real-world... by unixfg on Tuesday November 17, 2020 @11:38PM (#25133267)

A single core being able to fully saturate LPDDR4X bandwidth seems pretty advantageous.

https://www.anandtech.com/show/16252/mac-mini-apple-m1-teste...

“One aspect we’ve never really had the opportunity to test is exactly how good Apple’s cores are in terms of memory bandwidth. Inside of the M1, the results are ground-breaking: A single Firestorm achieves memory reads up to around 58GB/s, with memory writes coming in at 33-36GB/s. Most importantly, memory copies land in at 60 to 62GB/s depending if you’re using scalar or vector instructions. The fact that a single Firestorm core can almost saturate the memory controllers is astounding and something we’ve never seen in a design before.”

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Re:16-inch MBP 2x slower than M1 MacBook Air in a real-world... by Symmetry on Tuesday November 17, 2020 @04:16PM (#25129967)

You do get a power benefit from keeping the RAM in-socket rather than having to go out over more wires to reach the RAM.

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Re:16-inch MBP 2x slower than M1 MacBook Air in a real-world... by rbanffy on Tuesday November 17, 2020 @04:21PM (#25130015)

Isn't it attached via a wider bus?

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Re:16-inch MBP 2x slower than M1 MacBook Air in a real-world... by imtringued on Wednesday November 18, 2020 @03:14AM (#25134283)

The memory bandwidth you get on the M1 is around what you would expect from a dual channel desktop with good RAM. So basically twice as fast as competing laptops.

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Re:16-inch MBP 2x slower than M1 MacBook Air in a real-world... by wmf on Wednesday November 18, 2020 @12:34PM (#25139653)

Laptops have the same or faster RAM than desktops now.

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Re:16-inch MBP 2x slower than M1 MacBook Air in a real-world... by throwaway894345 on Tuesday November 17, 2020 @02:12PM (#25128236)

Ah, well I'm happy to be mistaken.

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