Why Windows 7 will automatically build 100M hidden partitions

Why does Windows 7 automatically create a 100M hidden partition? The situation described below may not be the only real reason, but it should be one. I don't know if someone else has sent it.

This is to make Win7 can be installed in the partition of the hard disk cluster larger than 4KB, because in NTFS format, the boot file can only work in the partition of 4KB cluster, this 100M is used to store the boot file of Win7. This installs Win7's primary partition and can be set to other sizes of clusters, even FAT32 format (to be verified).

We all know that the larger the cluster, the better the disk performance, the less fragmentation, but it will take up more space. Now the hard disk is big, and it is worthwhile to sacrifice some space for performance.

We can do this, CD-ROM boot, use Windows own partition function to establish 100M system partition first, then exit, U disk or CD into PM to establish the primary partition, and then specify the size of the cluster.