Since you're running VMware ESXi on HP ProLiant server hardware, your best bet is to install the HP CIM agents and utilities on the host to expose more detailed system health parameters to vSphere.
Which server model(s) are you using?
There are three components you need for an HP server running ESXi 5.1:
These get downloaded to a datastore and installed with:
esxcli software install vib /vmfs/volumes/datastore/<packagename>.vib
There's also an HP-specific build of ESXi that has all of this built-in. But the above process can be applied to a standard vanilla ESXi installation.