BiaB is a song creation tool and auto-accompaniment software.
Meant to be fast, basic easy-to-use tool for generating backing tracks.

RealBand (RB) started as a MIDI sequencer (named PowerTracks), then added audio multitracking capabilities, more ports for audio and MIDI, then once the ability to generate tracks from the same files BiaB uses was added, it became RB.. to this day it is a combination of Powertracks and BiaB in my eyes.

Because of this it is much different.
Generation is meant to be an 'intentional' action in RB; it is slower when mass generating BiaB tracks but can be more flexible than BiaB.

It doesn't have the 'read ahead' capability that BiaB does, which makes it seems like BiaB is faster .. however when you consider BiaB is dealing with 9 tracks and RB can have 48, there is going to be a difference.

Also, RB is meant to act more like a DAW as far as how features are implemented. So another reason it doesn't do the auto-generate/look ahead thing is because in a DAW environment you usually don't want tracks to keep changing. You are working on sections or single tracks..

Another example is using multi-riff. Because RB has more available tracks you can generate (say) a sax solo 8 times (all different variations) in one pass, all to different tracks, and then pick through what you like.
BiaB can't do that.

They ARE different, it just takes a while to see the difference.
And because of the different history, both need to be set up individually to work most efficiently.

Two simple things I notice help RB performance during any setup:
Don't run it from the same drive as the OS if possible (or at least take advantage of Temp Directory setting if you can).

Test your Driver settings and take a minute to look at what is being used and what is available. Experiment.
Ask questions, like you are..

When exactly does RB lock up?

I do not work here, but the benefits are still awesome
Make your sound your own!