I have a 10 year old, XP Pro 32bit machine with 4 GB of memory.....and it only takes about 20 seconds to a minute depending on the song and the tracks.

It tells me it's "Initializing Accompaniment". Even at startup it's only a minute.

So yeah, an hour seems extremely long. Even my old really slow laptop didn't take more than a minute or two at the most to generate the tracks in RB.

Larger context: Yep.... if you can play the tracks in question better than the RB RT players..... certainly. I do this all the time. Just mute the track it created and set up a new track to record your instrument.

More than one time, I have spent hours working on a part and in the end.... decided to work with the RB RT since it was clearly better. Either in tonal quality or performance. So.... don't delete the track until you're absolutely sure your track is the keeper.

You can find my music at:
www.herbhartley.com
Add nothing that adds nothing to the music.
You can make excuses or you can make progress but not both.

The magic you are looking for is in the work you are avoiding.