a tenth of the power of an SSME.
17.3MW is just the oxygen pump output, the hydrogen pump is by neccesity larger at an additional 53MW.
For some more comparable gas-generator turbopump power outputs:
The French Vulcain engine, with an oxygen turbopump at 3MW (hydrogen pump at 12MW)
The retired American J-2 of Saturn V, oxygen pump at 1.6MW (hydrogen at 5....
The SpaceX Raptor's preburners run at about 75 MW so about 37 times as much.
The SpaceX Merlin 1D turbopump (not strictly a preburner, as it dumps the exhaust) runs at about 7.5MW
The Shuttle's RS-25 preburners did some 17.3MW
On the other end of the scale, the Rocketlab Electron's pumps run at 38KW (*2) per engine. But those are purely electrical engines, ...