Apple Macintosh System 7.5 - Manual (Page 35)

Memory requirements
System 7.5 requires a hard disk and 4 MB of internal random-access memory
(RAM). To use PowerTalk or QuickDraw GX, or both, 8 MB of RAM is
required.
Upgrading RAM on Macintosh and PowerBook computers
Users with large programs such as graphics or page-layout programs, or users
who open several programs at once, will probably need additional RAM.
Macintosh and PowerBook memory upgrade kits are available from your
Apple dealer.
WARNING If you need to install more memory in a Macintosh or
PowerBook computer, contact your Apple-authorized reseller or
representative for assistance.
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