Most update build number for Windows Vista
Build 5536.16385 (released 24/08/2006)
This is Pre-RC1, Unlike Beta 2, only the x86 (32bit) version of 5536 is made available. However, the 32bit version will run fine on 64bit CPU's. This pre-RC1 build is available for a limited time – Microsoft will close the program when they reach 100,000 downloads.
Build 5600.16384 (released on 01/09/2006)
Now it is only available to Beta Testers.
Next week, a broader set of technical customers will get them via MSDN and TechNet.
NOTE:
There are a lot of improvements since Beta 2. MSFT has made some UI Adjustments, added more device drivers, and enhanced performance. If you are an ISV, RC1 is the build you should use for certifying your application.
You should use your same key(s) from previous releases. To generate a new key, please request from key package “5342 and Up – Ultimate” and “Beta 2 Home Basic/Home Premium/Business (v.5384)”.
Minimum Hardware Requirement for this 2 builds
Processor: 800 MHz 32-bit (x86) or 64-bit (x64) processor2
System Memory: 512 MB
GPU: SVGA (800x600)
HDD: 20 GB
HDD Free Space: 15 GB
DVD-ROM Drive