1) The CX3 was designed in early 2006. It is now a 7 year old array. Certainly not far to compare it to a P2000, which was designed int he last couple years.
2) Disabling the caches certainly wont help your performance
3) With a non-meta LUN you are only using 1 controller worth of performance
4) Are the RAID sets still zeroing/initializing? That wont help either.
5) You should understand that the CX3 is not supported with ESXi 5.1 in any way, shape or form.
