std::array vs array performance

What are the advantages of using std::array over usual ones?

It has friendly value semantics, so that it can be passed to or returned from functions by value. Its interface makes it more convenient to find the size, and use with STL-style iterator-based algorithms.

Is it more performant ?

It should be exactly the same. By definition, it's a simple aggregate containing an array as its only member.

Just easier to handle for copy/access ?

Yes.

A std::array is a very thin wrapper around a C-style array, basically defined as

template<typename T, size_t N>
class array
{
public:
    T _data[N];
    T& operator[](size_t);
    const T& operator[](size_t) const;
    // other member functions and typedefs
};

It is an aggregate, and it allows you to use it almost like a fundamental type (i.e. you can pass-by-value, assign etc, whereas a standard C array cannot be assigned or copied directly to another array). You should take a look at some standard implementation (jump to definition from your favourite IDE or directly open <array>), it is a piece of the C++ standard library that is quite easy to read and understand.

std::array is designed as zero-overhead wrapper for C arrays that gives it the "normal" value like semantics of the other C++ containers.

You should not notice any difference in runtime performance while you still get to enjoy the extra features.

Using std::array instead of int[] style arrays is a good idea if you have C++11 or boost at hand.