According to this MSDN page:
WOW64 enables 32-bit applications to take advantage of the 64-bit kernel. Therefore, 32-bit applications can use a
See this CodeCentral article: Using more than 3 GB memory in a 32 bit Delphi program.
In modern Delphi versions just add compiler directive to the dpr: {$SetPEFlags IMAGE_FILE_LARGE_ADDRESS_AWARE}
{$SetPEFlags IMAGE_FILE_LARGE_ADDRESS_AWARE}