What is the largest RAM expansion being manufactured today for Amiga and Commodore 8-bit?

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    "... you've seen" is kind of opinion-based, but it's an interesting question which could be split into two; what is the theoretically largest ram expansion there could be, and what was the largest ram expansion ever realized in practice? I believe there might not be theoretical limit if such extensions use bank switching though.
    – tuomas
    Feb 3, 2020 at 17:30
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    For what timeframe is this question. I am quite sure you in a short timeframe could make an add on card for the 2000 or greater using modern memories and get a rediculous amount of banked ram.
    – UncleBod
    Feb 3, 2020 at 17:45
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    Wow, I started to edit this to remove everything that's not a question. There's nothing left.
    – pipe
    Feb 3, 2020 at 18:02
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    Wouldn't it make sense to ask separate questions about Amiga and Commodore 8-bit?
    – cjs
    Mar 18, 2020 at 14:49
  • I find this question can be very informative - in fact, as a vintage computer collector I learned something practical for me from it. But I agree that it would make sense to have two separate questions for Amiga and Commodore 8-bit - those are two very different architecturally computer families.
    – moonwalker
    Aug 17, 2021 at 23:55

1 Answer 1


Big box Amigas (A3000/A4000) with Zorro-III 32-bit bus can accommodate 256MB RAM expansion cards, which are still being manufactured today. Utilizing 4 Zorro-III slots, this allows memory expansion of 1GB, which is quite substantial for a 68030/40/60 based computer. I'm not sure how you'd use it all, excepting some bespoke application that you could write yourself.

Small Amigas such as the A1200 usually only acquire large expansion memories when that RAM is fitted to an accelerator card. Most of those cards "only" support up to 128 MB. Still, a very substantial amount of memory on an Amiga.

The "standard" large memory expansion for the 8-bit Commodore machines is expansion cards that mimic the original Commodore Ram Expansion Unit ("REU"). First released alongside the C128, the REU allowed a C128 to be expanded to 640KB by providing up to 512KB, or 8 banks of 64KB. It is also compatible with the C64. However, the way the REU functions means it can support up to 256 banks of 64KB, or 16MB of expansion memory. Compatible REU's of this size are still manufactured today. You can use such "huge" REU's as RAM disks, and I know some demo scene productions have made use of them to create full-motion video.

  • The Sun2 supported/could use up to 8 MB (my own has 4) but this is due to restrictions in Multibus (i believe.) The RAM in later machines, for them it is a matter of what the motherboard supports. The 8 MB figure is possible in a large chassis 2/170 machine. This due to only 1 MB on each card. Feb 3, 2020 at 19:15
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    Just for completeness sake, "classic" Amiga with no accelerator (68000 CPU) max out at 11.75MB of RAM, 8MB Fast RAM, 2MB Chip RAM, 1.75MB "Pseudo-fast" RAM. [Note this requires a somewhat exotic config to reach this max. Both a 2MB Super Agnus upgrade chip (with 2MB on board) and a 2MB trap door card with Gary chip adapter, plus a standard 8MB fast ram expansion either on the external Zorro bus or mounted in the CPU socket. 8.5-10MB would be a more normal maximum depending on Amiga model.]
    – mnem
    Feb 4, 2020 at 10:37

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