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Old 01 December 2015, 18:07   #14
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Join Date: Dec 2006
Location: Delft / The Netherlands
Posts: 325
I asked on Cloanto's FB page for clarification about that 1GB thing. This is the reply i got.

What is the source of "+1 GB of RAM for OS4"? It might be some AmigaOS beta testers, or a speech by Hyperion at an Amiga30 event? Amiga Forever 2016 RAM options are covered here:

You can set Zorro III to 512 or more MB, but whether the OS uses that only for "swap" or as "real" RAM is up to the OS
Maximum RAM Supported by Amiga Emulation


Q: How much RAM does the Amiga emulation support?


A: In general, the maximum memory of all Amiga systems mirrors the limitations of the original hardware. As some applications and system functions may fail when using more RAM than was possible on the original Amiga hardware (e.g. 2 MB Chip RAM or 128 MB of Zorro III RAM), the original configurations are set to avoid unsafe settings.

In accordance with the original specifications, the Amiga Chip RAM is limited to 2 MB on newer Amiga systems (AGA chipset), and to 512 KB on early models (OCS chipset). The maximum amount of Fast RAM is always 8 MB. Systems with a 68020 or higher CPU further support up to 128 MB or more Zorro III RAM (which can be used instead of Fast RAM). Systems with expansion options further support up to 512 MB of RTG (retargetable graphics, or video) RAM, which is supported by the fully licensed Picasso96 software that is included with Amiga Forever.

The total memory space of the Amiga Zorro III expansion bus is 1792 MB, which is shared by pure RAM expansions, RTG video memory, and other peripherals. On A-4000 class systems (e.g. Workbench 3.X, Amiga 4000, AROS and WHDLoad configurations), the emulation can achieve a total of 1.5 GB Zorro III RAM by emulating two Zorro III expansion boards (1 GB + 512 MB), if peripherals like the RTG video memory leave room for it.

The process address space of the host environment also has an impact on the maximum contiguous memory that can be allocated. On 32-bit versions of Windows the maximum size of Zorro III RAM expansions may be about 512 MB. On 64-bit versions of Windows, the practical limit when using 32-bit versions of the emulation software (which is the current default) may be about 1 GB or 1.5 GB.

In order to allocate the maximum Amiga address space, Amiga Forever (2016 and newer) must be set to use the 64-bit version of the emulation. This can be achieved by setting the Use 64-bit version option in the Emulation settings (under Tools/Options in Amiga Forever).

In all cases, since the host environment's virtual memory functionality is inherited, it is possible to emulate an Amiga having more RAM than is actually available on the computer in which the emulation is run.
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