streaming samples with garageband

My son has a new Imac, getting into samples and running out of hard disc space.

Can he simply attach an external FW drive?

Are there faster options?

thanks. I ask because of my own experience trying to get the maximum polyphony from Synthogy Ivory on my Mac Pro. The only way I could get 60 note polyphony was to set up an internal RAID. I didn't try a faster drive because they were too small. I guess that's an extreme case, though