Choice of pressure washer for jetting drains

[smh]

I've heard some people have success with drain cleaning pressure washer attachments, although the pressure washers used by Dyno rod are some 10 times more powerful than the best 'DIY' stuff (i.e. karcher K785m/Bosch Aquatak). Can someone tell me what would be the difference between a DIY setup and the professional's gear in terms of moving caked-in limescale?

It doesn't matter if it takes me a little longer, I'm just concerned I might buy some gear that just doesn't do the job.

Thanks.