Size Comparison of 32-Bit and 16-Bit x86 Applications

Last reviewed: November 2, 1995
Article ID: Q97765

The information in this article applies to:

Microsoft Win32 Software Development Kit (SDK), versions 3.1, 3.5, 3.51, and 4.0

It is expected that a 32-bit version of an x86 application (console or GUI) will be larger than the 16-bit version. Much of this difference is due to the flat memory-model addressing of Windows NT. For each instruction, note that the opcodes have not changed in size, but the addresses have been widened to 32 bits.

In addition, the EXE format under Windows NT (the PE format) is optimized for paging; EXEs are demand-loaded and totally mappable. This leads to some internal fragmentation because protection boundaries must fall on sector boundaries within the EXE file.

The MIPS (or any RISC) version of a Win32-based application typically will be larger and require more memory than its x86 counterpart.

Additional reference words: 3.10 3.50 4.00 95
KBCategory: kbtool
KBSubcategory: TlsMisc

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Last reviewed: November 2, 1995
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