2 upvotes, 1 direct replies (showing 1)
View submission: I'm still struggling understanding RAM types/upgrades for OCS 500.
I'm not sure people here said it (I have not seen it).
As people said, the Amiga had "chip RAM", which is RAM where graphics and audio can reside, and for which there is contention with the CPU, and fast RAM, which is RAM the CPU can access without contention.
What I haven't seen anyone mention is that the belly expansion for the A500 resides on the contended bus only. If your chipset supports 1MB of chip RAM, this means you can have that memory be chip RAM (in which case you need to cut the jumper, so it appears at the correct address.
If your chipset does not support 1MB chip RAM, the memory you place there will appear at high addresses, normally associated with fast RAM. It will not, however, have fast RAM characteristics. It is still on contended bus, and will still be slow. This is sometimes referred to as "slow fast RAM".
There used to be a program in the AmigaDos diskette that told the computer not to use that memory, as it would get in the way of some programs.
Comment by spacemidget75 at 01/03/2025 at 17:55 UTC
2 upvotes, 1 direct replies
Amazing, thank you. I fully understand now. To get 1MB chip ram via the expansion, I need to make sure my A500 has the ECS version of the Agnus chip?