DuhSesame

mfryd said:

melgross said:

Ok, so the writer gets it wrong, as so many others have when it comes to the M series RAM packaging. One would think that’s this simple thing would be well understood by now. So let me make it very clear - the RAM is NOT on the chip. It is NOT “in the CPU itself”. As we should all know by now, it’s in two packages soldered to the substrate, which is the small board the the SoC is itself soldered to. The lines from Apple’s fabric, which everything on the chip is connected with, extend to that substrate, to the RAM chips. Therefore, the RAM chips are separate from the SoC, and certainly not in the CPU itself. As we also know, Apple offers several different levels of RAM for each M series they sell. That means that there is no limit to their ability to decide how much RAM they can offer, up to the number of memory lines that can be brought out. This is no different from any traditional computer. Every CPU and memory controller has a limit as to how much RAM can be used. So, it seems to me that Apple could, if it wanted to, have sockets for those RAM packages, which add no latency, and would allow exchangeable RAM packages. Apple would just have to extend the maximum number of memory lines out to the socket. How many would get used would depend on the amount of RAM in the package. That’s nothing new. That’s how it’s done. Yes, under that scheme you would have to remove a smaller RAM package when getting a larger one, but that's also normal. The iMac had limited RAM slots and we used to do that all the time. Apple could also add an extra two sockets, in addition to the RAM that comes with the machine. So possibly there would be two packages soldered to the substrate, and two more sockets for RAM expansion. Remember that Apple sometimes does something a specific way, not because that’s the way it has to be done, but because they decided that this was the way they were going to do it. We don’t know where Apple is going with this in the future. It’s possible that the M2, which is really just a bump from the M1, is something to fill in the time while we’re waiting for the M3, which with the 3nm process it’s being built on, is expected to be more than just another bump in performance. Perhaps an extended RAM capability is part of that.

Actually, moving the memory further away from the CPU does add latency.  Every foot of wire adds about a nanosecond of delay.

Then there is the issue of how many wires you run.  When the memory is physically close to the CPU you can run more wires from the memory to the CPU, this allows you to get data to/from the CPU faster.   It's not practical to run a large number of wires to a socket that might be a foot or more of cable run away.  That means you transfer less data in each clock cycle.

Generally socketed memory is on an external bus.  This lets various peripherals directly access memory.  The bus arbitration also adds overhead.


Traditional CPUs try to overcome these memory bottlenecks by using multiple levels of cache.  This can provide a memory bandwidth performance boost for chunks of recently accessed memory.  However, tasks that use more memory than will fit in the cache, may not benefit from these techniques.

Apples "System on a Chip" design really does allow much higher memory bandwidth.   Socketing the memory really would reduce performance.

lam92103 said:

So every single PC or computer manufacturer can use modular RAM. Including servers, workstations, data centers, super computers. 

But somehow the Apple chips cannot and are trying to convince us that it is not just plain & simple greed??

9secondkox2 said:

red oak said:

DuhSesame said:

red oak said:

So, it will launch against Apple’s M3, which is rumored to bring monster gains in performance and battery.   Good luck with that 

Also, where are Microsoft developers in creating ARM natively compiled software?     That will add another 12 months to their timeline in getting fully baked solution in the marketplace 

The M3 will likely based on A16, still a 4+4 with mild clock increase.

That said, I doubt Qualcomm will put out something better overall, we’ll see.

That would be three generations based on the A16.   We’ll see 

The move alone to 3 nm is going to provide 30% benefit.   Apple gets to decide how to divy that up between performance and battery life.    

I would not be surprised if M3 provides 30% performance overall (CPU and GPU)  AND 10% better battery life.    10% sounds low, but that’s another 2 hours at this point.    Substantial.    Or, Apple could decide to put it all into performance and get 40% better vs. M2.   That would be a real monster 

That would be without architectural improvements. M3 has been the goal for a couple years. M2 was always a stopgap, existing as basically an m1 plus. 

M3 cpu and GPU are being improved. Moving to 3nm is going to boost that further. 

It’s going to be a big deal in terms of performance. 

I can see the Mac Studio getting one update to m2 max/ultra and the Mac Pro arriving with an innovative m3 setup. The die shrink will also allow an M3 Ultra iMac to finally be released.