NPM Doesn't have out-of-the-box Hardware Health Monitoring for servers (it does have it for many popular brands of Networking equipment though, like Cisco, Dell Switches, F5's, Brocades, Juniper, etc...). If you want a strong Hardware Health Monitoring feature then you would need to add their SAM module onto it. SAM is their Server & Application Monitoring software. Its primary function is application monitoring. It'll tell you if services or processes are down, how much CPU/Memory/Disk IO each service/process are using as well as performance counter statistics and much, MUCH more. It also has Hardware Health Monitoring that will talk to your Dell, HP, and IBM servers (provided you have the Dell OpenManage/HP Insight/IBM Director installed on them).
For virtual devices, it will get hardware health information from VMWare vCenter and/or VMWare ESX Hosts (although it is always better to monitor all of your ESX hosts through your vCenter server if they are managed by one, you should only poll ESX Hosts directly if they are not managed by one). Without SAM, NPM will only tell you about volume usage (Capacity, Disk I/O, Disk Queue Length), CPU & Memory usage of the server, and current status (Up/Down/Reboot, Response Time, and Packet Loss).
From NPM you can get hardware health information with a little bit of effort by using Custom Universal Device Pollers. You would need to enable SNMP on your ESX hosts, set them up in Orion using the same community strings you configured on the hosts, then open the Universal Device Pollers application on your primary Orion Server, then browse through there until you find the hardware health information you want to poll. Using Google you should also search around for SNMP MIB information to tell you where specifically in the MIB Browser in the Orion UNDP application to look. Sorry I can't give exact information right now but I don't have access to an Orion system from home. If you need more specific info just let me know and I'll add more when I can.
humejo is correct and it listed on the SolarWinds kb: SolarWinds Knowledge Base :: Hardware Health: SAM & NPM Differences
Using NPM, you can poll the HDD for events such as low available space - which is most common type of alert for volume monitoring.
UnDP can grab some hw info, but it's a time intensive process. I Had several clients who tried to do this, but after spending a week in lost productivity - they went ahead and installed the evaluation SAM and within a matter of 30 minutes they had the alerting and reporting setup for hardware. They ended purchasing the product, I would say that all of the clients I have work with do not have the time to go through the process of manually setting up custom pollers. Gone are the days of MRTG and people want to get the monitoring up quickly so they can move on to other issues.
If you really want to set up UnDP, we can walk through the process of doing a SNMPWALK on the device, looking at the MIB definitions for the device form the vendor, and constructing the hardware monitoring. I have done this many times for clients who have specialized equipment.