What is better in regards to performance at runtime: Explicit casting or 'as'/'is syntax [duplicate]

What is better in regards to performance at runtime: Explicit casting or
'as'/'is syntax [duplicate]

References

Reference NO 1

http://stackoverflow.com/questions/15185785/what-is-better-in-regards-to-performance-at-runtime-explicit-casting-or-as-i

Reference NO 2

http://stackoverflow.com/questions/7544233/difference-between-implicit-conversion-and-explicit-conversion

Reference NO 3

http://en.wikipedia.org/wiki/C_Sharp_(programming_language)

Reference NO 4

http://www.bytearray.org/?p=4789

Reference NO 5

http://dev.mysql.com/doc/refman/5.0/en/information-functions.html

Reference NO 6

http://confluence.jetbrains.com/display/Kotlin/Comparison+to+Scala

Reference NO 7

http://grails.org/Application+metadata

Reference NO 8

#EANF#