After reading some other posts on the internet and doing some testing with Iometer, I would recommend these changes to the configuring of multipathing (from the presentation of "Open-e V6 MPIO with Vmware ESXi 4.x"):
on page 8 from the presentation: esxcli nmp roundrobin setconfig --type "iops" --iops 1 --device <device UID>
remove the line about which changes the bytes.

General benchmarking:
http://blog.peacon.co.uk/benchmarkin...ge-for-vmware/

Here are some other related posts about it:
http://www.boche.net/blog/index.php/...n-emc-storage/
http://www.ivobeerens.nl/?p=465

Derek