Apple iMac with Fusion Partitioning: Benefits of Partitioning, and How-To
Thanks to Other World Computing for making the iMac available for testing, as well as the 32GB of 1600 MHz memory and OWC Mercury Helios / Accelsior SSD.
The benefits of partitioning a Fusion volume are explained in Controlled Fusion: Partitioning for Targeted Performance as well as How to Partition A Fusion Drive.
The same thing applies to any Mac with a Fusion setup.

186GB SSD+HDD Fusion volume (partition)
using diglloydTools DiskTester fill-volume data
using diglloydTools DiskTester fill-volume data