You're right. It's a cardano-node wallet's component, who is guilty for excessive CPU usage. There's nothing you can do about it. It consumes over 100% of CPU power, even though Daedalus wallet is a passive full node. With the release of a cardano-light-node utility, the situation will be dramatically changed for the better.
By the way, the Bitcoin Core full node app consumes approximately 25% of CPU power.