Why is 15W Apple M1 CPU+GPU SoC so fast? When will the PC industry go Unified Memory ?

[WowoW]

Why The Apple M1 Chip Is So Fast - A Developer Explains | Production Expert (pro-tools-expert.com)

Apple's Humongous CPU Microarchitecture - Apple Announces The Apple Silicon M1: Ditching x86 - What to Expect, Based on A14 (anandtech.com)

And yet we still stuck with DDR4 on desktop PC...

 

Edited April 19, 2021 by vietanhngdinh2901

[emosun]

From what I've seen the cpu is only fast "considering its power usage" and isn't fast in any other respect.

I would sooner use a 10,000$ ddr4 machine than the m1

[mariushm]

Almost none of the things in the article are the reason the m1 faster. 

 

Unified memory was already done by AMD ... it's not something new.

The article says about how much faster videos play on M1 ... that's all because the M1 has hardware video decoder in the video card, while the old mac's video card had no hardware decoder for h264 or vp9 or whatever the video was encoded with. 

Even the cheapest amd or intel gpu with integrated graphics has hardware decoders so that's nothing new. 

 

The DRAM in the M1 is either ddr4 or ddr5 ... it's not something revolutionary or new.  Also unified memory is also done in game consoles, where you have stuff like 12 GB of GDDR5, 2-4 GB being used by the operating system and the rest by the video card.

 

M1 is faster and more efficient for some things, because it's ARM and because it's low nm (expensive manufacturing process). 

AMD's Ryzen processors have to deal with x86 and backwards compatibility, supporting mmx, sse, sse1, 2,3, 3.1, avx, avx512, and a crapton of other extensions to the x86 architecture. It will probably still run a program compiled to use only the 386 instruction set.

 

All these extra instructions make the x86 more versatile, easier to write programs for, but it means the cpu uses more power to process each instruction.

The M1 being arm has a more reduced instruction set and the programs are often optimized specifically for it.  An Adobe premiere is compiled specifically for M1 processor, while on x86 that Adobe premiere has to run on a 10 old cpu, has to run on a laptop, has to run on threadripper and has to run on lots of hardware... it makes it harder to optimize.

 

The M1 has some clever bits, but it's nothing revolutionary.... i see the "neural engine" which for me is buzzwords and would probably never be used by 99% of the people buying a laptop with m1 processors 

 

[SorryBella]

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Why is 15W Apple M1 CPU+GPU SoC so fast?

Well, a lot of things that i know someone else in this thread will have even more insight about, but generally its the reduced bloat of instructions in ARM compared to x86, Rosetta 2 magic sauce, experience of Apple with ARM chips, tight mac os and its hardware integration, and other small optimization that makes it tick in both software and hardware level. BUT it doesnt mean its fastest pound per pound, its fastest per watt.

 

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When will the PC industry go Unified Memory ?

Not soon i believe, considering that PC consumer really wants user upgradability/repairability.

[Chris Pratt]

A lot of this is ironically market driven. SoC has a number of performance benefits, but in order for it to work, literally nothing is upgradeable. LTT recently did a video discussing how motherboards work where they talked about some of the legacy things there. Like having only two slots for dual channel is better for performance, but mobos continue to use 4 slot designs because consumers like the idea that they can slot more RAM in later (even though they rarely do on the whole).

 

This has been the secret to the success of consoles for a long time. No one expects to be able to upgrade a console's hardware, so they're free to solder to their heart's content. That allows far better performance than the typically middling specs of their individual components, and it's why the next gen consoles, now with actually high end CPUs, are such powerhouses.

 

It's not really a question of when the PC market is going to go here: it's not. You may be leaving performance on the tables, but consumers demand separate, easily replaceable components in their PCs, and that's not going to change.