If you have enough processing power. Without a GPU it's going to lag.

In my experience, a small/tiny whisper model has pretty okay English decoding speed on something relatively modern even without GPU support. There's a bunch of latency in the process (because of technological limitations) but the optimised C++ version shouldn't pose too much of a problem unless you're running in power saving mode. Battery life may be a problem on older laptops, though.

Whisper is pretty fast.