I'm using a similar setup with PrimoCache on a windows server 2016 OS, running both as a file server and as a iSCSI storage host for virtual machines running on other hosts
So far I've been satisfied with the results on a 10GB network. been able to max out linespeed on everything that lands in the cache
storage behind primocache is an LSI 9271-8i with 6*6TB in raid 5. Second level cache consisting of a fine raid 0 pair of S3710 SSD's found through these forums.
I'm reaching on average a 35% cache hit on combined usage.
cache settings are in the screenshot aswell
quick disk bench from a virtual windows 10 with storage on iSCSI