After some more testing with directly attached LUNs, I consulted this document again http://www.equallogic.com/WorkArea/DownloadAsset.aspx?id=10771 and I think I may have resolved my problems.
- I have disabled autotune on the interfaces in my R710 with:
netsh int tcp set blobal autotuninglevel=disabled
- On the switches I've re-enabled iSCSI optomizations, flow control, and Port Fast on all interfaces.
- I've also renabled Jumbo Frame support on the Broadcom NICs, Switches, and SAN after disabling it for testing.
Before making the switch changes all three LUN types were performing horribly.