In Win32, DLL's are "pre-linked" using a specified base address. When the DLL is loaded, an attempt is made to place it at that address. If that address is already in use, a new base address is selected, and the DLL subject to fixups. Apparently, these fixups are very slow, and significant performance gains can be made by selecting a good base address. This document is to allocate base addresses to core Python and Python .PYD files, to give a better change of optimal performance. This base address is passed to the linker using the /BASE command line switch. Python.exe/Pythonw.exe - 1d000000 - 1e000000 (-1) Python.dll - 1e000000 - 1e100000 (-1) Standard Extension Modules 1e100000 - 1e200000 "" - _symtable 1e100000 - 1e110000 - bsddb 1e180000 - 1e188000 "" - _tkinter 1e190000 - 1e1A0000 - parser 1e1A0000 - 1e1B0000 - zlib 1e1B0000 - 1e1C0000 - winreg 1e1C0000 - 1e1D0000 - _socket 1e1D0000 - 1e1E0000 - _sre 1e1E0000 - 1e1F0000 - mmap 1e1F0000 - 1e1FFFFF More standard extensions 1D100000 - 1e000000 - pyexpat 1D100000 - 1D110000 - select 1D110000 - 1D120000 - unicodedata 1D120000 - 1D160000 - winsound 1D160000 - 1D170000 - bZ2 1D170000 - 1D180000 - datetime 1D180000 - 1D190000 - _csv 1D190000 - 1D1A0000 Other extension modules - win32api 1e200000 - 1e220000 - win32ras 1e220000 - 1e230000 - win32lz 1e230000 - 1e240000 - timer 1e240000 - 1e250000 - mmapfile 1e250000 - 1e260000 - win32pipe 1e260000 - 1e270000 - avl 1e270000 - 1e270000 - dbhash 1e280000 - 1e290000 - win32net 1e290000 - 1e2A0000 - win32security 1e2A0000 - 1e2B0000 - win32print 1e2B0000 - 1e2c0000 - 1e2d0000 - 1e2e0000 - win32gui 1e2e0000 - 1e2f0000 - _imaging 1e2f0000 - 1e300000 - multiarray 1e300000 - 1e310000 - win32help 1e310000 - 1e320000 - win32clipboard 1e320000 - 1e330000 - win2kras 1e330000 - 1e340000 - pythoncom 1e340000 - 1e400000 - win32ui 1e400000 - 1e500000 - win32uiole 1e500000 - 1e600000 - pywintypes 1e600000 - 1e700000 - win32process 1e700000 - 1e800000 - odbc 1e710000 - 1e720000 - dbi 1e720000 - 1e730000 - win32file 1e730000 - 1e740000 - win32wnet 1e740000 - 1e750000 - win32com.shell 1e750000 - 1e760000 - win32com.internet 1e760000 - 1e770000 - win32com.exchange 1e770000 - 1e780000 - win32com.exchdapi 1e780000 - 1e790000 - win32com.axscript 1e790000 - 1e7a0000 - win32com.axdebug 1e7b0000 - 1e7c0000 - win32com.adsi 1e7f0000 - 1e800000 - win32event 1e810000 - 1e820000 - win32evtlog 1e820000 - 1e830000 - win32com.axcontrol 1e830000 - 1e840000