Yes, an 8-year old laptop could be the culprit. When I look at my "modern" 6-year old iMac with 16 GB of RAM and a Quad-core Intel i5 processor, my System CPU usage is under 4%, where yours is almost 64%.
On a Mac since 1984. Currently: 24" M1 iMac, M2 Pro Mac mini with 27" BenQ monitor, M2 Macbook Air, MacOS 14.x; iPhones, iPods (yes, still) and iPads.
