Hacker News Reader

Comment by jsheard | Hacker News Reader

Then again, the rest of the industry has figured out a way to make slottable RAM almost as fast and compact as soldered RAM with the new CAMM2/LPCAMM2 standards. The M4 has LPDDR5X-7500 120GB/sec memory and there are already LPCAMM2-7500 120GB/sec modules, with even faster ones on the way: https://www.anandtech.com/show/21390/micron-ships-crucialbra...

Two of those modules working in parallel would hit "M Pro" speeds as well. I doubt Apple will be adopting them though, for the same reason they don't offer standard M.2 SSD slots even on systems that could obviously support them with minimal design compromises.

View on HN

These are still well below what Apple offers at the high end and you can not buy systems like that right now. If you want high memory bandwidth on the CPU today, you will be charged a big markup on Epyc/Xeon/ThreadripperPro CPUs and motherboards, rather than the DRAM.

> Then again, the rest of the industry has figured out a way to make slottable RAM almost as fast and compact as soldered RAM…

Just be patient, the EU will take a large stick and force Apple to allow users to replace their RAM soon too.

Very unlikely. Apple can argue that less than 1% of computers users ever upgrade their memory (which is true), and after all, did the EU intervene when GPUs dropped their slotted memory?

> did the EU intervene when GPUs dropped their slotted memory?

The difference there is that slotted GPU memory is demonstrably impactical, but the memory on the M4 isn't demonstrably better than the LPCAMM2 module above. It's literally the exact same spec. Not that I expect the EU to do anything either when they didn't act on Apples soldered-in SSDs, which definitely aren't any better than standardized M.2 drives.

Actually, incorrect. On some scenarios, you’d need up to 4 CAMM2 slots to do what Apple does. This is due to CAMM2 maxing out at 128 bit busses; but M3 Max chips are currently at 512. Needless to say, battery life most affected.

https://news.ycombinator.com/item?id=40287592

Yes, the higher end Max and Ultra chips would still need soldered memory for sure. Two CAMM modules flanking opposite sides of the SOC is probably doable though, so I think the M Pros could practically have socketed memory.

GPU memory is 20 MT/s+, Apple is ~6 MT/s, LPCAMM supports ~7500 MT/s.

Easy heuristic: if your memory transfer rate is more than 1.5x the standard, you can solder RAM. If not, you must use the standard.

Reply on news.ycombinator.com