This sort of thing use to be done a lot back in the day. Especially before the more powerful multicore processors became available. In fact their use to be hardware units manufactured specifically for this purpose (v-machine, Muse Receptor, AudioStation, etc). That and using vst's in live performances before laptops became stable enough to do the job. I remember certain soundcards had onboard synths or samplers and fx to offset some the cpu stress giving you a similar effect.