Mag Computer Memory

A Mag history of RAM (1960-2025)

The most immediate measure of complexity of a computing system is online memory. In basic computational theory, if a system has N bits of memory, it has the potential for 2^N different states. And while a theoretical Turing machine has an infinite tape and can therefore perform any computational task, in practice all computers have limited memory and therefore limited capabilities.

Other measures of computer performance (like calculation speed, offline storage, and networking bandwidth) progressed at roughly the same exponential rate as memory. For example, as a general rule of thumb, systems have about ↑2 more permanent storage than memory–a 1985 IBM PC probably had 512kB of RAM and a 40MB hard disk, and a 2024 MacBook Pro can have 36GB RAM and 4TB SSD.

So, the available RAM of a system is a reasonable proxy for its computing power (at least on a mag scale). Here’s an overview of RAM in various computer systems over the past 50+ years. Remember, this is a log scale:

There are several amazing arcs plotted here:

Nintendo’s entire line of console games, from the original Game & Watch (↑2 in 1980), up to the ↑9 Switch in 2017. And their corresponding handheld line that was historically at least one mag lower, until it converged with the Switch.
Five generations of PlayStations, quite a straightforward exponential progression (though this trend has slowed with the PS5).
iPhone. Its RAM growth has been “only” ↑2, but there were numerous other impressive developments, from camera to display to battery, so Apple made many more incremental releases (whereas console manufacturers only release the next generation when it’s at the next level).
Apollo Guidance Computer (1966, by the PDP-8). It was a relatively light minicomputer and it only had ↑3 memory, but it was space-hardened and it got them to the ding dang moon.
The dips at the ends of some product lines. These are the results of companies trying to make a late entry-level model in the same product line. Interestingly this strategy often indicates the end of a line, because some other nascent product will come to carry the torch into the next magnitude or two or three–before it’s displaced and the cycle begins anew.

Finally, note that going from 256 bytes of RAM in the Altair 8800 (1975) to 128GB RAM in the MacBook Pro (2024) is a ↑9 increase. That’s a billion times more memory–nine orders of magnitude in 50 years.

Moore’s Law

Many of the levels of computing power were driven by Moore’s Law, as the process node size went from ↑-2 for vacuum tubes (1950s), to ↑-3 for discrete transistors (1960s), to ↑-5 for the first semiconductor (1968), and to ↑-9 for modern semiconductors (2024).

That ↑7 decrease in node size accounts for 7 of the 14 levels of computing we have available to us today.

We’ve been dealing with this pace of development for at least 50 years, so at this point it probably feels ‘normal’ and like it will continue indefinitely. But every one of these levels was a big deal, and required a major scientific discovery or technological innovation. The early ones could be done by a single smart person or a small team, but every level is more challenging than the last, almost by definition.

The most advanced process node size is ↑-9. A Hydrogen atom is ↑-10 size. It has been a tremendous feat of science and economy that Moore’s Law has gotten us this far, and now we’re hitting a wall (see The Memory Wall: Past, Present, and Future of DRAM for an in-depth explanation of DRAM, including the state of the industry in 2024).

Mag Data

The general scale of data:

↑-1 (bits): yes/no
↑0 (bytes): one word
↑3 (kB): one page of text
↑6 (MB): one song
↑7: one music album
↑8: one video (10 minutes)
↑9 (GB): one movie
↑12 (TB): consumer microSD card (2025)
↑22: all data ever (2020)
↑23: all data ever (2025)