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Apple’s new M1 Pro and M1 Max processors

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Re: Apple’s new M1 Pro and M1 Max processors

#441

Post by phkahler »

jjoonathan wrote: post #271
Unklejoe wrote: post #211

Earlier quoted context omitted.

The overall bandwidth isn't affected much by the distance alone. Latency, yes, in the sense that the signal literally has to travel further, but that difference is miniscule (like 1/10th of a nanosecond) compared to overall DDR access latencies. Better signal integrity could allow for larger busses, but I don't think this is actually a single 512 bit bus. I think it's multiple channels of smaller busses (32 or 64 bit…

DRAM latencies are pretty heinous. It makes me wonder if the memory industry will go through a similar transition to the storage industry's HDD->SSD sometime in the not too distant future. I wonder about the practicalities of going to SRAM for main memory. I doubt silicon real estate would be the limiting factor (1T1C to 6T, isn't it?) and Apple charges a king's ransom for RAM anyway. Power might be a problem though.…

>> I wonder about the practicalities of going to SRAM for main memory. I doubt silicon real estate would be the limiting factor (1T1C to 6T, isn't it?) and Apple charges a king's ransom for RAM anyway. Power might be a problem though. Does anyone have figures for SRAM power consumption on modern processes?

I've been wondering about this for years. Assuming the difference is similar to the old days, I'd take 2-4GB of SRAM over 32GB of DRAM any day. Last time this came up people claimed SRAM power consumption would be prohibitive, but I have a hard time seeing that given these 50B transistor chips running at several GHz. Most of the transistors in an SRAM are not switching, so they should be optimized for leakage and they'd still be way faster than DRAM.

Re: Apple’s new M1 Pro and M1 Max processors

#442

Post by spacedcowboy »

enraged_camel wrote: post #255
danielovichdk wrote: post #252

I feel happy for the Apple community with these processors. But I can't stop to think my Intel machine. It feels like I am left in the dust and nothing seems to be coming that remotely looks like the M1.

Intel is years behind Apple, with no real strategy for catching up. Apple most likely already has the M2 ready, and the M3 under heavy development.

M2 was sent for manufacture earlier in the year, if you believe the rumor mill (and to be fair, they were spot on this time around)

Re: Apple’s new M1 Pro and M1 Max processors

#443

Post by SkeuomorphicBee »

haberman wrote: post #415

I always thought it was strange that "integrated graphics" was, for years, was synonymous with "cheap, underperforming" compared to the power of a discrete GPU. I never could see any fundamental reason why "integrated" should mean "underpowered." Apple is turning things around, and is touting the benefits of high-performance integrated graphics.

> I never could see any fundamental reason why "integrated" should mean "underpowered."

There was always one reason: limited memory bandwidth. You simply couldn't cram enough pins and traces for all the processor io plus a memory bus wide enough to feed a powerful GPU. (at least not in a reasonable price)

Re: Apple’s new M1 Pro and M1 Max processors

#444

Post by hatsubai »

Gene_Parmesan wrote: post #370
bla3 wrote: post #118

Earlier quoted context omitted.

I thought the memory was one of the more interesting bits here. My 2-year-old Intel MBP has 64 GB, and 8 GB of additional memory on the GPU. True, on the M1 Max you don't have to copy back and forth between CPU and GPU thanks to integrated memory, but the new MBP still has less total memory than my 2-year-old Intel MBP. And it seems they just barely managed to get to 64 GiB. The whole processor chip is surrounded by…

Just some genuine honest curiosity here; how many workloads actually require 64gb of ram? For instance, I'm an amateur in the music production scene, and I know that sampling heavy work flows benefit from being able to load more audio clips fully into RAM rather than streaming them from disk. But 64g seems a tad overkill even for that. I guess for me I would prefer an emphasis on speed/bandwidth rather than size, but…

Another anecdote from someone who is also in the music production scene - 32GB tended to be the "sweet spot" in my personal case for the longest time, but I'm finding myself hitting the limits more and more as I continue to add more orchestral tracks which span well over 100 tracks total in my workflows.

I'm finding I need to commit and print a lot of these. Logic's little checker in the upper right showing RAM, Disk IO, CPU, etc also show that it is getting close to memory limits on certain instruments with many layers.

So as someone who would be willing to dump $4k into a laptop where its main workload is only audio production, I would feel much safer going with 64GB knowing there's no real upgrade if I were to go with the 32GB model outside of buying a totally new machine.

Edit: And yes, there is does show the typical "fear of committing" issue that plagues all of us people making music. It's more of a "nice to have" than a necessity, but I would still consider it a wise investment. At least in my eyes. Everyone's workflow varies and others have different opinions on the matter.

Re: Apple’s new M1 Pro and M1 Max processors

#445

Post by jjoonathan »

rdw wrote: post #305
Unklejoe wrote: post #211

Earlier quoted context omitted.

The overall bandwidth isn't affected much by the distance alone. Latency, yes, in the sense that the signal literally has to travel further, but that difference is miniscule (like 1/10th of a nanosecond) compared to overall DDR access latencies. Better signal integrity could allow for larger busses, but I don't think this is actually a single 512 bit bus. I think it's multiple channels of smaller busses (32 or 64 bit…

Your comment got me thinking, and I checked the math. It turns out that light takes ~0.2 ns to travel 2 inches. But the speed of signal propagation in copper is ~0.6 c, so that takes it up to 0.3 ns. So, still pretty small compared to the overall latencies (~13-18 ns for DDR5) but it's not negligible. I do wonder if there are nonlinearities that come in to play when it comes to these bottlenecks. Yes, by moving the R…

Well, you can have high bandwidth and poor latency at the same time -- think ultra wide band radio burst from Earth to Mars -- but yeah, on a CPU with all the crazy co-optimized cache hierarchies and latency hiding it's difficult to see how changing one part of the system changes the whole. For instance, if you switched 16GB of DRAM for 4GB of SRAM, you could probably cut down the cache-miss latency a lot -- but do you care? If you cache hit rate is high enough, probably not. Then again, maybe chopping the worst case lets you move allocation away from L3 and L2 and into L1, which gets you a win again.

I suspect the only people who really know are the CPU manufacturer teams that run PIN/dynamorio traces against models -- and I also suspect that they are NDA'd through this life and the next and the only way we will ever know about the tradeoffs are when we see them pop up in actual designs years down the road.

Re: Apple’s new M1 Pro and M1 Max processors

#446

Post by lillecarl »

dragontamer wrote: post #405
culpable_pickle wrote: post #398

Earlier quoted context omitted.

Why? There are plenty of server oriented ARM platforms available for use (See AWS Graviton). What benefit do you feel Apple’s platform gives over existing ones?

The Apple cores are full custom, Apple-only designs. The AWS Graviton are Neoverse cores, which are pretty good, but clearly these Apple-only M1 cores are above-and-beyond. --------- That being said: these M1 cores (and Neoverse cores) are missing SMT / Hyperthreading, and a few other features I'd expect in a server product. Servers are fine with the bandwidth/latency tradeoff: more (better) bandwidth but at worse (h…

My understanding is that you don't really need hyperthreading on a RISC CPU because decoding instructions is easier and doesn't have to be parallelised as with hyperthreading.

Re: Apple’s new M1 Pro and M1 Max processors

#447

Post by dragontamer »

Unklejoe wrote: post #126
PaulKeeble wrote: post #109

Earlier quoted context omitted.

400GB/s available to the CPU cores in a unified memory, that is going to really help certain workloads that are very memory dominant on modern architectures. Both Intel and AMD are solving this with ever increasing L3 cache sizes but just using attached memory in a SOC has vastly higher memory bandwidth potential and probably better latency too especially on work that doesn't fit in ~32MB of L3 cache.

The M1 still uses DDR memory at the end of the day, it's just physically closer to the core. This is in contrast to L3 which is actual SRAM on the core. The DDR being closer to the core may or may not allow the memory to run at higher speeds due to better signal integrity, but you can purchase DDR4-5333 today whereas the M1 uses 4266. The real advantage is the M1 Max uses 8 channels, which is impressive considering t…

> The M1 still uses DDR memory at the end of the day, it's just physically closer to the core. This is in contrast to L3 which is actual SRAM on the core.

But they're probably using 8-channels of LPDDR5, if this 400GB/s number is to be believed. Which is far more memory channels / bandwidth than any normal chip released so far, EPYC and Skylake-server included.

Re: Apple’s new M1 Pro and M1 Max processors

#448

Post by spacedcowboy »

out_of_protocol wrote: post #171
sk0g wrote: post #115

Now, if only Unreal Engine builds were available M1 native, I could get rid of my huge and heavy desktop entirely! Interestingly, some improvements to Rosetta were mentioned, extremely briefly.

Apple very much against games, they've even broken OpenGL just because. Don't expect any type of gaming ecosystem around Apple anytime soon.

So against games that they just became a Patron supporter of Blender [1]...

[1] https://www.blender.org/press/apple-joins-blender-developmen...

Re: Apple’s new M1 Pro and M1 Max processors

#449

Post by watermelon0 »

pb7 wrote: post #407
paavohtl wrote: post #385

Earlier quoted context omitted.

If Apple actually cared about sustainability, they would make their devices repairable.

They are repairable, but not by consumers in most cases.

They are mostly not repairable even by authorized repair providers.

Basically, they can only change a few components (keyboard, display (with assembly), motherboard, and probably the aluminium case), but that's it.

Re: Apple’s new M1 Pro and M1 Max processors

#450

Post by soheil »

It's a bit concerning that the new chips have special purpose video codec hardware. I hope this trend doesn't continue, requiring laptops from different manufacturers to play different video formats or at least with a non-degraded quality.
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