Here is a picture that perfectly describes my situation:
Is there some way I can smooth this transfer out to be near 90% usage by increasing a buffer somewhere? It seems like windows grabs a chunk of the drive, empties the cache, then waits for the drive to grab another. Instead of pulling data off the disk as constantly.
Windows Small Business Server 2011 hosted on an ESXi (.vmx and .vmdk are on mirrored SSD's) box pushing a 10gb file to a FreeNAS machine (capable of 100MB/s transfers from other clients) over iSCSI (need direct block access for SBS2011 backups.)
Looking in the FreeNAS monitoring it's averaging around 600Mb/s.