It is likely to be related to Topology polling that is done every 30 minutes. You can change the topology frequency to be some thing less agressive - like once a day
There are some useful suggestions in this thread
You may want to check if it's relevant to you as well
In addition to what holy said- I have had a specific issue with a version of NX-OS where the mib-bridge topology poll was causing high CPU due to a bug. Removed mib-bridge from config and it was fine till upgrade- moral of story- start a support case with Cisco.
This has been an on again, off again issue with Cisco for many years. Just perform a simple Google search for "cisco high cpu snmp" and it comes back with a lot of information. I've not seen this issue in recent IOS versions as much, so maybe you have some devices with older code? Typically, the high CPU is caused when polling for the mib-bridge information or the routing table.
As a big fan of Solarwinds Orion, my advice would be to upgrade your version of code on the device(s), and see if that helps. As this is an SNMP issue, it's not going to matter what tool you use to poll for information via SNMP, you are going to have the same issue.