It was using Model 3 Hardware. VF4 used Sega NAOMI 2 Hardware, which could have been for Dreamcast because it could handle both Model 3, NAOMI, and NAOMI 2, but the console died. VF3 came out in 1996, while VF3tb came out a year later.
It was supposed to be for Saturn and the console was supposed to have a better RAM, but Saturn also failed as well.