Microsoft's Chris Flores writes in the Windows Vista Blog that the dispersion of 64 Bit operating systems tripled over the last three months.
64 Bit is advancing
This insight is based on statistics gather via Windows Update. Accordingly the share of people in the USA that use the 64 Bit version of Vista, has been tripled in almost no time. Furthermore about 20 percent of the systems connecting to Windows Update is using 64 Bit - in March only 3 percent did. It seems like x64 is advancing.
One of the advantages of 64 Bit is that it is possible to use 4 or more GiByte Ram. With a 32 Bit operating system this is not fully possible. Especially Vista gains a huge benefit in this respect. Since 32 Bit applications run on a 62 Bit OS, too, there is only little reason not to change to 64 Bit. And as soon as 64 Bit is established, more programs are bound benefit from the structure.