One of the frequent questions our staff are asked is whether Diskeeper for Windows x64 operating systems (AMD64/EM64T – CPUs) is native or compatible? By compatible, that of course means it runs in 32 bit mode; native referring to it running in 64 bit mode. Beginning with Diskeeper 10, the Professional editions (and above) have operated entirely in 64 bit mode. We recompiled the software and made the necessary edits to offer this to users running x64 operating systems. While unexpected, we did see some slight performance gains. One of the perks of x64 architecture, as noted in's x86-64 entry is: "very large files can be operated on by mapping the entire file into the process's address space (which is generally faster than working with file read/write calls), rather than having to map regions of the file into and out of the address space." If you're a avid video editor or engineer working with CAD/CAM 4GB+ files (not uncommon these days), you've likely been running Windows XP x64 for some time. As Diskeeper 10 had a multiple component architecture, both the scheduling service (dkservice.exe) and the defragmentation engines (DfrgNTFS.exe and DfrgFAT.exe) ran in native 64 bit mode. In Diskeeper 2007 all operations are controlled directly under the Diskeeper Service (still called DKService.exe), and it too runs native x64. When you download and extract the purchased software you'll notice right away that you receive two instances of Diskeeper. One installation program is for x86 and the other for x64. Each comes in an independently labeled folder. An autorun.exe program will properly select the install file to execute. If you have an x64 processor but a 32 bit Windows, you will need to install the 32 bit version of Diskeeper; the autorun program will handle that for you as well. The same support in Diskeeper (Professional editions and above only) will be available for Vista x64 operating systems as well.