Generally speaking, yes, but depends what "locations" means.

In order to increase performance, they must reside on different physical disks. This means different spindles, not logical volumes on the same spindles.

Data and log files are read and written with very different I/O patterns:

data files --> mostly random reads and writes

log files --> mostly sequential writes

Separating those I/O patterns can improve performance and recoverability.

Hope this helps

Gianluca