Which partition is fastest?

Which partition is fastest? 

Drive speed varies from outer tracks to inner tracks, by simple math (circumference X data density), see Why you need more space than you need.

When making more than 1 partition on the same drive, the first one listed is fasters (outer tracks), and the last one listed will be slowest (inner tracks). For SoftRAID, the first partition created is fastest, the next one created is next-fastest, etc.

Schematic of a disk platter (not to scale)
Observe the difference in circumference

A drive capable of 100MB/sec might decline in speed from 100MB/sec down to a sluggish ~60MB/sec. Exploiting this fact can guarantee high performance for many uses.  

For example, installing a 2TB drive and using the first 1TB is substantially faster than using a 1TB drive, by about 25%.

 

*Please refer the post about "Partition Hard Drives in Apple Mac"