From os.amigaworld.de:
AmigaOS 3.9 - Requirements
In order to upgrade your Amiga system to OS 3.9, it must be equipped with the following hardware:
* CD-ROM drive
* Hard drive
* 68020 or higher processor
* Amiga 3.1 ROMs (Version 40.xx)
* 6 MB Fast RAM
For improved performance we recommends adding::
* 68030 or higher processor
* 8 MB Fast RAM
* Graphics accelerator and/or scandoubler
* Modem
To take full advantage of OS 3.9 we also recommend you add the following:
* 68060 processor with PowerPC accelerator card
* 16-Bit sound card
* 32 MB Fast RAM
* I/O Accelerator
