The CPU usage and RAM usage would be pretty low, but then you should notice a big jump in your bandwidth usage.
CPU usage is substantial on my laptop during synchronization and on incoming transactions. Of course it's an older model.
If you want to help the network the CPU should be able to validate transactions quickly enough.
When you are doing initial sync, your CPU is handling 5 years' tx in a day or two, and so it is normal to have a busy CPU.
But for running a full node, your CPU just need to handle a few tx a second, and so the CPU usage should be lower.