Seems that this discussion misses some technical details. RAM: The number 1 reason for going 64bit is RAM. 32bit Windows can only *address* (aka 'use') about 3.2-3.5 GB of RAM, and on systems with GPUs that have a large amount of dedicated RAM this number can even drop to 2.x GB. This has to do with the address space. However, 64bit Windows and 64bit programs usually use more RAM than their 32bit versions - this is due to the smallest available data unit being 64bit instead of 32bit, twice the size! *Some* data structures (not the application as a whole) will occupy up to twice as much memory as 64bit version (compared to 32bit) - I don't have any real world numbers for common applications or the Windows core system, but the factor is surely far below the theoretical value of 2x. Another restriction is that on 32bit Windows a single process can only allocate up to 2 GB memory maximum. So 64bit Windows is required on systems with more than 4 GB, and/or systems with less than 4 GB depending on the hardware setup in order to be able to actually *use* all of the installed memory. On systems with 3-4 GB the increased memory consumption of applications might outweigh the benefit of allowing to use all of the installed RAM. Performance: 64bit software does not magically improve performance, software has to be optimized for 64bit, and significant improvements can only be expected for certain CPU intensive tasks. Adobe Photoshop states that it speeds up 'only some operations' and those not 'equally', and gives a figure of 8-12%. At the same time 32bit software will be executed in the WoW (Windows on Windows) environment, and run up to 10% slower on 64bit Windows 7 due to the management overhead.