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Is this too good to be true? Apple insists 8GB unified memory equals 16GB regular RAM

I read the article, and it boils down to "Trust me," which, were I a power user running RAM intensive processes, I wouldn't be all that gung-ho to buy into.

Perhaps the answer is to take advantage of Apple's 14 day return period to try the lesser RAM out, but there's an "opened memory" caveat to returning, and I can't find what that actually means.

The "how it's measured" point reminds me of the old horsepower argument where American automobiles always appeared to have a lot more than British cars. But, each country's manufacturers took different approaches to measurement.

The Brits measured the horsepower that was actually delivered where it mattered: where the tire met the road. That is, the output of the engine after delivery through the transmission, drive shaft, differential, axles......

The Yanks preferred to have the engine mounted on a stand and take measurements without going through any power-draining components.

So, both could make true statements about horsepower but......

It is not just unified memory per. se. that enables Macs to need less RAM. It is the culmination of multiple memory management technologies over the last several years all designed in preparation for fully implementing unified memory in hardware.

At the most elementary level…

• Data is not processed in memory, it is processed in registers in the processor
• The majority of CPU cycles are spent waiting for data to move from and to memory.
• Memory is a storage media for temporary data elements and a buffer between the processor and storage
• If the memory is big enough to keep the data transfer channels between the processor and memory filled and the idle CPU cycles waiting on data transfer at the absolute minimum, more memory cannot improve performance.
• Unified memory's speed improves the effectiveness of other memory management tactics such as "compressed memory" significantly more effective.

There are exceptions to this, most notably in older applications such as Adobe's suite, that ignore macOS memory management in favor of their own memory management that was designed decades ago when the OS memory management was not up to the task.

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NOTE: To re-iterate the preceding is all at the most elementary level… and there are innumerable factors at play and literally billions of "moving parts" so the equivalency is unlikely to ever be 100%, but in specific cases it could be more than 100%. IMHO the next big hardware evolution will be to eliminate any distinction between memory and storage.

CONFESSION: Having said all that, and having been more than satisfied with the performance of an M1 Mac Mini with 8GB of RAM, when I upgraded to an M1 Max Mac Studio I opted for 32GB of RAM and it appears that approximates overkill.

Thanks for that clear, excellent explanation, but I don't follow the overkill part. To us uninitiated, it looks like 16GB would be too little.

I think you are still looking at the memory usage in the way everyone used to. I am looking primarily at memory pressure that is flat and low which indicates there is ample memory available. Ignoring that I am not using all of the available memory and in recent versions of macOS, optimum performance is achieved when all memory is used and the OS is programmed to meet that goal. What I see in the screenshot indicates is I could easily be running more or bigger — more memory intensive — tasks or to put it a different way I paid good money for memory that is unnecessary.

This screenshot shows the RAM usage on your M1 Max Mac Studio with 32GB of RAM on top and that of my Intel Mac with 16GB of RAM on the bottom.

Although they're almost identical in RAM usage, my pressure is higher than yours, presumably because your hardware is so much more advanced than mine, but I'm still left wondering what each of our pressures would be were we to have 16GB and 8GB, respectively? Presumably, both of our pressures would increase, but I'd love to know by how much, and how our performance would be affected.

And to add to the mix, here is my RAM usage (bottom, in dark mode) with 16 GB of RAM on a Mac Mini with an M2 Pro.

It seems to be very comparable to Artie's in terms of pressure.

Think of "Memory Pressure" as how hard the memory management system is having to work to meet the overall system memory demands. Both of our memory pressures are in the green which means neither is overstressed. Assuming approximately equivalent tasks are running on both machines, your RAM pressure is higher than mine because you have less RAM therefore increasing your "pressure" or the amount of resources needed for memory management. Starting more tasks running or more memory intensive tasks on either machine would increase the memory pressure.

That's obvious, but my bottom line question is how our memory pressures would change under the same running circumstances if we each had half as much RAM as we've got?

Is it possible to gauge at what point our pressures would change to red?

I am quite certain that it is possible, otherwise how would macOS know to change the color. However I am not privy to either the formula or the specific metrics used in that calculation. If you are really interested, you might try digging through the developer's manual — an AI assisted search engine is recommended — but there is a better than even chance that information is only available in Cupertino.

I was thinking from the point of view of our judging how much RAM we really need to buy.

In a more user-friendly day we could have swapped RAM in and out to see how our pressure changed, but Apple has backed us into buying too much of their overpriced RAM out of fear that we may be buying too little.

You really won't like the future when the entire computer including memory, storage, display, keyboard, and all the support functions are all on the same fabric, but that is coming sooner rather than later. Oh wait! It is already here. Apple calls it the iPad Pro.

But that begs the question, which is were you to have 16GB RAM rather than 32, or I 8, rather than 16, is there any way to estimate its effect on memory pressure in contemplation of out next Macs?

For instance, could we both go with stock RAM and be satisfied that our needs will be met? As I said, Apple has kind of backed us into buying too much out of fear of buying too little.

The only real way I can think of to have surety is to buy or rent the new machine and try it out for a few weeks or months.

Besides that, my needs are continually evolving. For example, I am currently experimenting with half a dozen new apps in search of the ideal editor, and over the weekend I deleted several others I either found unsatisfactory, I was no longer needing, or in two cases (both memory hogs) the developers has lost interest any the app was no longer working. Add to that I am now using multiple AI utilities, plugins, search engines, and tools. I have no feel for what those will have on system resources. Heaven only knows what changes next month will bring.



A precious few people in Cupertino know what's next and when. But the technological trend is toward greater integration and fewer plugins therefore fewer opportunities for customization. If memory and storage merge into a single entity, which is a logical step, there would be no need to consider "memory" per. se.. With that in mind all any of us can realistically expect do is look at the trends, examine our bank balance, honestly assess our needs, make a semi-wild A guess at our requirements and end up buying what we want rather than what we need.


The entire device on a single "blanket' was foreseen half a century ago but we couldn't envision all of the implications. I am planning on being around to see what happens in the next round or two. (Can you imagine a quantum computer with a petabyte of storage/memory as a wearable device? It is at or very close to the engineering stage now.)

Taking advantage of Apple's 15 day return policy may be the best answer.

(Is it technologically possible to create a tool that would enable you to use only a portion of your installed RAM - in effect, take one or more DIMMS "off-line" - and thereby judge how much you actually need? Seems like there'd be a fortune to be made for an enterprising developer.)

I'd like to see it integrate with Musk's Neuralink chip.

"I robot" could transition to "me robot."

I can imagine the physical reality, but I can't begin to guess about the actual need for such a thing, although I suspect that it wouldn't be anything I'd want involved in my life.