Shared Folder slower than Hyper-V VHD/PassThrough?

Our users currently access their files directly on our VNXe from Shared Folders.  We're thinking of moving towards a Windows Server "file server" setup to utilize some of the features Windows Server offers for file servers.  The file server would be a Hyper-V machine, with the data probably on a Pass Through disk to the VNXe over iSCSI.  I figured surely this would be a little slower, since data has to go in and out of the Hyper-V host, rather than straight to the VNXe Share.  I ran a couple speed tests several times, one with thousands of small files, and one with a single large file.  When copying straight to the VNXe share both tests were approximately 20% slower than when copied through the Hyper-V machine's share of a pass through disk, over iSCSI, to the VNXe.  Even copying to the VM's drive C (a VHD) was equally as quick as the pass through disk.

How is the indirect route faster?  Is there that much overhead involved in a Shared Folder that when combined with the speed of direct writes over iSCSI, it makes the extra hop through the Hyper-V machine irrelevent?  Both the Share and iSCSI storage are on the same storage pool.