The PPMd algorithm uses a custom memory management system called SubAllocator. In a zip file, the memory size the SubAllocator uses is defined in the WinZip PPMd header for the compressed file and this header's value is used when decompressing the data. In general, WinZip uses 64Mb. Since the algorithm used was not optimized from the original PPMd version I revision 1, the SubAllocator initially requires the total amount of memory specified in the PPMd compressor. This means you must have at least 64 free Mb of RAM when using this compression method.
Target Platforms: Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2