Run the 'top' command.

The third line says what the CPU is doing or waiting on.

us: userland processes, aka your programs cpu usage. sy: system, things running in the kernel, can be things like quickly opening and closing network sockets ni: mixed processes, generally ignore, only above 0 if you are ratelimiting cpu for specific processes id: percent idle time wa: cpu is blocked waiting for things like disk or network hi: hardware interrupts si: software interrupts st: steal, if you are on a VM and the parent is restricting your cpu usage, potentially for a noisy neighbor.

If the cpu ghz is not significantly slower than your other pc I would guess it is likely high io wait