Sony Designed the Original PlayStation for 16MB RAM, Modders Just Delivered It

The original PlayStation console launched with only 2MB of main RAM, split across four 512KB chips soldered to the motherboard. That amount served the system well for its era, powering a library of games that still hold up today. Yet the central processor inside was built from the start to work with up to 16MB. Sony simply never populated the extra capacity in consumer units, even though some of its own arcade hardware ran with the larger amount in two separate 8MB banks.

A PlayStation modder dubbed TunerTom has recently filled the RAM gap. Using traces from arcade boards and PSX.Dev Discord discussion, he has prepared a 16MB upgrade package that works on the standard PlayStation system. Another key step for this project was when Tito Perez of Macho Nacho Productions helped spread the word by performing a full, on-hardware demonstration, replete with a before-and-after test run.

The upgrade does not modify the actual size of the chip footprint on the console’s motherboard, but almost everything else is redesigned. The first stage involves removing the conventional four 512KB chips. In their stead are eight 2MB EDO RAM chips salvaged from old 16MB RAM modules used in PCs. Four of these chips are inserted into the board connectors in the proper orientation. The remaining four are carefully changed so that they may stack directly on top of one another, with all but one of the legs soldered to the chip below, leaving one pin free for a particular connection.


The most difficult aspect is all of the extra wirework that must be completed, as here is where the majority of the modification effort is concentrated. It treats the extra memory as two independent 8MB banks, exactly as other arcade systems did. After cutting a few traces on the original motherboard and exposing a via, you can use a custom quick-solder adapter board shared by another modder in the community to route memory control signals. A short wire harness reconnects the bank-select pin to the adapter, and a single 22-ohm resistor completes the circuit. Plus, if you put the RF shield back on, the upgrade remains hidden within the original case.


The good news is that the upgrade should be compatible with the console’s easier to mod models, such as the SCPH-5500 with the PU-8 motherboard. With a little additional work, it may also work on other console revisions. You’ll need a hot air gun to remove the old chips, steady hands for soldering, a craft knife to cut some of the traces, and a multimeter to perform basic continuity checks. I’d rate it as an intermediate level challenge for an experienced console modder, however the adapter board does assist minimize the amount of point-to-point wiring required.


Testing has shown that the upgrade not only works, but also delivers. A special utility disc tests the PlayStation’s stock 2MB RAM, and once the mod is complete, it is changed to accommodate the 16MB RAM.


Most of the games you have already work properly because they never required more than 2MB of RAM. Some games, however, now fail to boot or simply crash due to a problem with memory initialization or the way the old setup replicated part of the data. However, the console itself continues to function normally on a daily basis. The true gain comes when game developers or homebrew programmers begin to design software that makes full use of all that extra capacity. Homebrew projects may suddenly have a lot of area for larger textures, longer draw distances, or just being able to load more assets from disc. Tito discovered one example: a Super Mario 64 port that can now load the entire game into RAM at once.