ScuzzBlog: Diaries March 2023
Entry 3rd March 2023: Post 1: Amiga 500 - A 512K upgrade is all you need.
Amiga 500 - A 512K upgrade is all you need.
I thought I would start my 2023 session with some quick answers
to a few queries that seem to dog the various forums. First up
the simple truth about Amiga 500 memory upgrades.
This is a simple answer. I also provide the long detailed one
with the link below.
The Amiga 500 was used primarily as a games machine. It was the
most popular Amiga ever released because of this reason.
During its lifetime the games sold for the machine became a
little more demanding. Nothing too heavy, but a simple 512K of
memory was all you needed to enjoy these kinds of games. The
box for games in the day would always advise of the memory that
was required and if more than the 512K already onboard would
state that 1MB was needed. And that meant a 512K expansion card
in the trapdoor.
The most common trapdoor expansion for the Amiga 500 was the
A501 provided by Commodore. Not all RAM cards had clock expansions
but for the stock Amiga 500 they were always 512K.
The Amiga 500 has 512K RAM available as CHIP RAM. This accounts
for the 512K always fitted on the motherboard to the Amiga 500.
CHIP RAM is the memory allocated for use with the custom chips.
Any expansion RAM is classed as FAST RAM and is primarily used
by the CPU for everything else. The different RAM is accessed
on alternate clock cycles which although alternately used does
not slow the machine down.
The later Amiga 500s were shipped with an upgraded AGNUS and was
able to access 1MB CHIP RAM but was still only fitted with 512K
though having empty slots on the motherboard for more memory.
In addition to the 512K memory expansion the Amiga 500 can handle
up to 8MB RAM which would have normally been provided using a side
expansion unit such as the GVP or A590. The trapdoor memory can
only manage 512K without modifying the motherboard.
There are a number of work arounds and clever gadgets to expand
the CHIP memory but these involve modifications to the main board
and that is the subject of my more detailed explanation.
In truth an Amiga 500 only needs a 512K memory expansion to the
trapdoor slot. The boards were ten a penny in the day and still
find their way onto EBAY. There is no other mysterious magical
simple trick to adding more memory, nor is there any real need to
do so. 512K is all you need and seriously forget CHIP RAM.
L I N K
The A500 memory [ more complex answer ].
Amiga 500 - A 512K upgrade is all you need.
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Last updated 3rd March 2023
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