DimplesAkaKaren noticed that Windows came with two versions of Internet Explorer. She asked the Answer Line forum which she should use. - The 64-bit versions of Windows 7 and Vista come with both 32- and 64-bit variations of Internet Explorer. But the operating systems default to using the 32-bit brower.
They do this for a good reason: backward compatibility. Plug-ins have to be rewritten to work with the x64 version, and a lot of plugins have yet to be rewritten. More 64-bit plugins are being released all the time, of course, so this problem isn't as severe as it used to be. For instance, you can now download and install 64-bit versions of Adobe Flash Player and Google Toolbar. But if Windows were to default to running the 64-bit browser tomorrow, it would still result in a lot of frustrated tech support calls.
Nevertheless, if the plugin limitations don't bother you, there are reasons to use Internet Explorer x64. For instance, the 64-bit browser can use 4GB or more of memory.