HP ML110 G6 with P212 and 256 cache module

Hello,

I have a ML110G6 with HP Smart Array P212 card (462828-B21)and 256 cache module(462968-B21), 3 500GB SATA disks on RAID5.

I've installed ESXi 5.5 but find the disk speed quite low. ESXi is installed on USB disk.

I got 2000 ms peaks latency while performing disk tasks, like installing OS's from ESXi local datastore (this is, ISO's are on the same ESXi).

I tired to copy 100 Gb from one folder to another on the same disk (mainly nsf files, this is, not small ones), and it took many hours.

Does anybody thinks that with the HP 462969-B21 650 mAh P-Series Memory Back-up Battery will increase speed and reduce this latency?

Does anybody know that I also need the HP 650 mAh P-Series Battery (462969-B21) to enable BBWC will help?

Thanks,