64 - bit client Blizzard has released the 64 - bit client ( Patch 4 . 3 . 2 build 15211 ) for Windows and Mac OS X for Live servers . Looking through the first few pages of the forum post , most reviews are positive , as would be expected . The client will only work with Patch 4 . 3 . 2 32 - bit client already installed . On 14 - Feb - 2012 , an updated 64 - bit client ( Patch 4 . 3 . 3 build 15314 ) for Windows and Mac OS X was released to match the PTR update on 18 - Feb - 2012 . On 22 - Feb - 2012 , links for build 15338 were updated on the PTR 64 - bit client forum page and then to build 15354 . The 64 - bit client should now also work on European realms . Up thru 1 - Feb - 2012 , European realms did not support the 64 - bit client . In World of Warcraft , a 64 - bit client ( theoretically optimized for 64 - bit OSes ) was introduced for testing on the PTR as of Patch 4 . 3 . 2 for Windows clients only . A Mac client was released later when the client was updated to build 15201 . When Patch 4 . 3 . 3 ( build 15534 ) went live , 64 - bit client download links were not provided immediately , but added about 3 hours later , although some were provided for the PTR earlier . On March 27th , 2012 , a Patch 4 . 3 . 4 ( build 15499 ) PTR 64 - bit client was made available for download on the PTR Discussion forum ( US ) . On April 2nd , 2012 , the build version was updated to 15531 , but with no additional info . On April 14th , 2012 , build 15595 appeared on the PTR , but no 64 - bit client until April 16th , 2012 . Although Patch 4 . 3 . 4 went live on April 17th , 2012 , it was still in testing for about 7 hours before the 64 - bit version was made available . You still need to remove old x64 files before using the launcher / updater to get your other files to the latest patch , before trying to launch as x64 . Mists of Pandaria Beta . After build 15657 , the 64 - bit client should download automatically with any client releases . Any exceptions will be noted below . Mists of Pandaria Beta 64 - bit client history . A 64 - bit client for Windows ( WoW - 64 . exe ) was quietly downloaded with build 15640 of the that was noticed by some users and clarified by an . The key difference between this test release and previous Live and PTR releases was that it was installed with Launcher and did not have to be installed manually . Bluspacecow predicted correctly that a 64 - bit Mac OS X client ( World of Warcraft - 64 . app ) would be available with build 15657 . Sadly , there was no Mac 64 - bit client available for build 15668 and Blizz ard said previous users must switch to the 32 - bit client via the Launcher ' s Game Preferences dialog . Unfortunately , the Launcher might get in a vicious cycle where it would download a corrupt file ( incomplete ? 32 - bit ? ) , detect it , and disable the Game Preferences menu item . If this occurs , users are advised to delete the wow - 0 - 15668 - OSX - final . MPQ file from their Updates / directory and try to select " Launch 32 - bit client " from the Game Preferences before the corrupt file finished downloading . Afterwards , users would likely have to delete the wow - 0 - 15668 - OSX - final . MPQ file " again " and then the 32 - bit update should proceed normally on the next Launcher start . After successfully switching to the 32 - bit client , everything should be fine . On May 10th , 2012 , minor progress was made with the 64 - bit client for build 15677 , as the client downloads and launches successfully for both Mac and Windows , but crashes immediately after character selection . Continuing the 2 - day cycle , build 15689 was released later May 12th , 2012 and the 64 - bit client is working again . If you encounter issues . If you encounter any issues while using the 64 - bit version , please report your findings in this thread and return to using the 32 - bit executable . In order to facilitate support when contacting Technical Support , please inform them if you are using the 64 bit client . To remove the 64 - bit client completely , delete the following files from your World of Warcraft folder : Difference from 32 - bit client . The difference is not major initially . Moving up to a 64 - bit client means that data can be moved around in larger chunks by the OS and application . It also allows the client to access more memory and thus store more quickly accessible content if the player ' s computer has more than 4 GB of RAM ( which many do ) . Recent benchmarks ( on build 15171 ) show an improvement , but usually less than 15 % . Performance is still also limited by the CPU and video subsystem . A 64 - bit client will not work on a 32 - bit OS , but most 64 - bit OSes have a 32 - bit compatibility layer for 32 - bit applications .