access constant memory

Hi,

I asked the constant memory problem early.

And I understand that access constant memory is faster than access global memory.

But the kernel code I programmed is the same speed when I placed the array in constant or global memory , and two cases as shown :

*******constant memory*******

kernel test(constant int * a){

...

int n = rand (); // rand() function is used to generate a integer number and n is not the same for each workitem

int tmp = a[n];

...

}

**************************

*******global memory*******

kernel test(global int * a){

...

int n = rand (); // rand() function is used to generate a integer number and n is not the same for each workitem

int tmp = a[n];

...

}

**************************

Therefore , each workitem might not access the same address of array a.

These cases result in same speed (kernel time)

In nvidia guide , if access constant memory address is not the same address , it will be access sequentially.

Is it the same as Altera OpenCL ?

Thanks