I want to give 70.640 active directory
exam.
But some people say that 70.640 exam has changed to 83.640
but their is no info about that on MS website.
Can someone confirm that please.
You should contact Microsoft directly for this sort of question.
Both still exist, both still grant a MCTS, both count towards a MCITP & here in Oz, both are available via Promtric testing centers, but to quote Microsoft...
This Technology Specialist (TS) exam, Exam 83-640: TS: Windows Server 2008 Active Directory, Configuring, became available in November 2008. This exam maps to the same objectives as 70-640, but this version (where available) contains a Performance Based component in addition to the standard exam item types. This exam is available in English only.
My understanding is that a Performance based component is MS speak for a simulation - if you like them do this exam, hate them do the other. Since the 83 exam is in English only it is highly unlikely that there is any downside to taking the 60 exam.