Supported Memory Size - Windows Vista And Windows XP
Regardless of which version of Windows you are using, all 32 bit systems are limited to a maximum of 4 GB of RAM. The only exceptions to this rule are the Starter Editions, which are primarily targeted at developing nations.
|Windows Vista||32 bit||64 bit|
|Ultimate||4 GB||128 GB|
|Enterprise||4 GB||128 GB|
|Business||4 GB||128 GB|
|Home Premium||4 GB||16 GB|
|Home Basic||4 GB||8 GB|
There is only a single 64 bit version of Windows XP, which is identical in feature set with Windows XP Professional. From a technical perspective, it is built around the Windows 2003 Server kernel (Version 5.2).
|Windows XP||32 bit||64 bit|
|Professional||4 GB||128 GB|
|Starter Edition||512 MB||-|