Did you ever get an answer to this? We just added a PowerConnect 5424 today and I see that Orion doesn't seem to recognize CPU/Memory. I've just begun my search for the answer but thought I'd check here first.
Do you have the OID for CPU/Memory? If so, you can use it with our Universal Device Poller (UnDP).
Apologies, I misunderstood. If you can't find the OID after a MIB Walk, try contacting Dell and requesting them to update their MIB.
When you have the OID, Chapter 12 of the Orion NPM Administrator Guide gives information on using it to build the UnDP.