So buy the tool you need and amortize the cost by being more effective. It pays back more, which is why I doubt your entire crusade. Your behavior is bizarre TBH.
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M3 Pro/Max have lower memory bandwidth
- Thread starter leman
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Wow. That's pretty slick (albeit more or less in line with the discount trend on M1 Pro/Max MBPs we've been seeing the past few months)
It's been a long time since I've seen a new Apple product so badly shown up by a product two years/generations older than it
Even in the best case scenario for the M3 Pro (whenever the embargo drops) a 64GB/2TB M1 Max is likely a far better deal (and may even be faster for a lot of things)
I'd love to be wrong but... essshhh it's looking like if you need a new Mac folks, consider the M1 Max... not exactly the advice I was expecting to give post M3 Pro/Max launch.
No, otherwise you’d be saying positive things about your experience with your choice. Instead you’re just spreading and supporting FUD.
Can you quote me on my fud? Nearly the entire forum is unhappy with M3's SKUs. Why are you singling me out?
I was interested to see this change in P and E cores and then slightly confused when I saw the battery life numbers.
I did not expect the Pro to be significantly lower from the base M3 for battery life and I also didn't expect the Max to be in line with the Pro for battery life.
I wonder if real world this isn't accurate. Or, its accurate for the Max, and the Pro actually has a better battery life than advertised.
I think it makes sense? The 14” chassis has the same battery, so outfitting it with a bigger SoC will increase the average power draw. The 16” has a larger battery, which can compensate for that power draw.
That makes sense with the larger SOC drawing more power. Certain tasks will obviously be faster with the Pro over the base.
However, for tasks like web browsing how much faster is it that its sacrificing 20% battery life per cycle. That seems weird to me.
Another example in Apple specs is Apple TV playback. Again the M3 base has 20% more battery life per cycle for completing the same task. Am I seeing this wrong? There is a certain amount of CPU or GPU that is needed, why would it require more from the Pro over the base to accomplish? They both have P and E cores that are clocked, we assume, the same.
Battery life is dominated by the baseline (idle) power consumption. M3 Pro has more memory chips/channels, more cache, bigger on-chip network etc. All these things consume energy. It’s very possible that the baseline power consumption of the larger chip is 0.5 watts higher - this alone would account for the discrepancy in battery life.
Wait a minute, are we sure that even the top M3 Max 16 CPU / 40 GPU is always running the four memory channels? Asking because the 48 GB ram could be 3 x 16 Gb ram blocks and that you would need to go for the 64 GB ram to get to 4 x 16 GB ram with all four memory channels running? 🤔
48 GB could be 4 x 12 GB ram blocks of course…
Apple’s tech specs claim it’s the full 512 bit bus. And a small note: it’s not four channels, it’s 8/16/32 channels (depending on how you count).
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That makes sense. I am hoping Apples reported battery life is for the Max and the Pro will be better since the Max has more of all the above factors you listed.
Can you provide a link to that? I see this - https://support.apple.com/kb/SP899?locale=en_US. But I am still a little concerned that the 48GB 16 core M3 Max is using 3 x 12GB (96Gbit) ram and thus only 3 channels = 300 GB/sec bandwidth ... the apple specs don't seem entirely clear.
I think the Apple specs are very clear. Max with 14 cores is 300GB/s, Max with 16 cores is 400 GB/s.
Also, why are you saying that 300GB/s are 3 memory channels? How are you counting the channels?
oops, my bad, I meant "a little concerned that the 48GB 16 core M3 Max is using 3 x 16GB (128Gbit) ram ... "
Likely you are right. Just wondering if you had other Apple docs/links specifying this. I also like this table of permutations - https://forums.macrumors.com/threads/m3-chip-generation-discussion-megathread.2393667/post-32679222
Understood about number of 'channels' - I think that many people, myself included, think of each 'chip' having roughly 50GB/s bandwidth. So there are two way to get to 48GB - 8 chips of 6GB each, or 6 chips of 8GB each.
I think it's all in the document you have linked earlier + the tech specs on the Apple Store page. It is a bit confusing with all the RAM sizes, that's true.
https://forums.macrumors.com/threads/m3-chip-generation-discussion-megathread.2393667/post-32679222
RAM is packaged differently across the different models, so it's not the most reliable way to count it. But with the LPDDR5 Apple uses 50GB/s correspond to 64-bit memory bus, which makes it easy to determine the bus width of the different models. Memory channels are a bit more messy because it depends what one counts. From what I understand LPDDR5 operates with 32-bit channels, which operate as two independent 16-bit channels (to make it even more confusing). Regular DDR operates in 64-bit channels, except DDR5 also moved to 32-bit channels for more flexibility. Generally, I don't think that channels are a very helpful metric nowadays for the end customer, I'd rather look at the bus width.