Buffer.BlockCopy vs. Array.Copy

[kellox]

Does anybody know the difference between the two static methods Buffer.BlockCopy and Array.Copy? It is said that Buffer.BlockCopy is faster than Array.Copy since it only checks boundary and then moves the content with the system call m_memmove.
According to the documentation though, Buffer.BlockCopy works with primitive types such as byte, char, etc.

But I've found a case where Buffer.BlockCopy doesn't work as it should (or maybe I'm missing something about Buffer.BlockCopy):

char[] c1 = { 'a', 'b', 'c', 'd', 'e' };
char[] c2 = new char[5];
Buffer.BlockCopy(c1, 0, c2, 0, 5);
 

If one analyzes the content of c2 after the Buffer.BlockCopy execution, one can see that the content of isn't "abcde" but "abc"
If I do an Array.Copy instead of Buffer.BlockCopy, the content of c2 becomes "abcde" as expected.

I'm a bit confused since I always thought that those methods actually will do the same thing as long as primitive types are used.

[ZiadElmalki]

Buffer.BlockCopy works as bytes. The chars 2 bytes a piece. Change the size to 10.