SQL Server NTFS allocation unit size
You shouldn't need to uninstall/install: your data and log files should be on separate disk arrays/SAN Luns from the binaries.

Saying that, 64k NFTS cluster is highly recommended all over the place.
SQL Server does IO in extents which is 8x8k pages = 64k, basically.

For actual numbers on performance differences, I can only find this http://tk.azurewebsites.net/2012/08/ (Azure, but still SQL Server)