What happens when the drive is formatted differently? On smaller drives such as 64GB you would like to keep the cluster size small, so you won't loose much space when files do not complete a cluster. The bigger the drive or partition and the bigger the filesize the bigger the cluster size should be. As the benchmark shows, using 512 Bytes for a Cluster does diminish performance.
On a small drive it seems that 1kB Clusters would be the best option, because it gives you the best performance. If you have bigger drives, 2k and 4k seem viable options too.