-- Program 1
#include <stdio.h>
#include <stdlib.h>

#define MAX_CNT 500


int main(int argc, char** argv)
{
    int i, j, k;
//    int test_data[MAX_CNT][MAX_CNT][MAX_CNT];
    int*** test_data;

    test_data = calloc(MAX_CNT, sizeof(int**));
    for(i = 0; i < MAX_CNT; i++)
    {
        test_data[i] = calloc(MAX_CNT, sizeof(int*));
        for(j = 0; j < MAX_CNT; j++)
        {
            test_data[i][j] = calloc(MAX_CNT, sizeof(int));
        }
    }

    for(i = 0; i < MAX_CNT; i++)
    {
        for(j = 0; j < MAX_CNT; j++)
        {
            for(k = 0; k < MAX_CNT; k++)
            {
                test_data[i][j][k] = 100;
            }
        }
    }

    return 0;
}


Result
$ time ./main

real	0m0.539s
user	0m0.367s
sys	0m0.172s


-- Program 2
#include <stdio.h>
#include <stdlib.h>

#define MAX_CNT 500


int main(int argc, char** argv)
{
    int i, j, k;
//    int test_data[MAX_CNT][MAX_CNT][MAX_CNT];
    int*** test_data;

    test_data = calloc(MAX_CNT, sizeof(int**));
    for(i = 0; i < MAX_CNT; i++)
    {
        test_data[i] = calloc(MAX_CNT, sizeof(int*));
        for(j = 0; j < MAX_CNT; j++)
        {
            test_data[i][j] = calloc(MAX_CNT, sizeof(int));
        }
    }

    for(i = 0; i < MAX_CNT; i++)
    {
        for(j = 0; j < MAX_CNT; j++)
        {
            for(k = 0; k < MAX_CNT; k++)
            {
                test_data[k][j][i] = 100;
            }
        }
    }

    return 0;
}

Result
$ time ./main

real	0m5.344s
user	0m5.202s
sys	0m0.147s