Reserved Memory Size

Common Options : 64KB, 32KB, 16KB, Disabled

Quick Review

This is an ISA-specific BIOS option. In motherboards that have ISA slots, the BIOS can be set to reserve part of the upper memory area (UMA), which resides between 640 KB and 1 MB, for use by ISA expansion cards. This is particularly important for older operating systems like MS-DOS because it frees up conventional memory (the first 640 KB) for use by the operating system and applications.

If your ISA expansion card requires an upper memory area of 64 KB in size, select the 64KB option. Similarly, if it requires just 32 KB or 16 KB of upper memory, select the 32KB or 16KB options respectively.

If you are not sure how much memory your ISA expansion card requires, select 64KB. It will work with cards that only require 32 KB or 16 KB of upper memory. The rest of the reserved upper memory area will be left unused.

If you do not have any ISA expansion cards installed, leave it at its default setting of Disabled. This frees up the UMA for use by the operating system (or third-party memory managers) to store TSR (Terminate and Stay Resident) programs.

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