You'll need at least a GeForce5200 or an ATI9600 (or lower?).
I know you can't run parallax mapping on a GeForce 3 ti200, and a Geforce 4 MX is below that, so somewhere above a GeForce 3 range.
I know you can't run parallax mapping on a GeForce 3 ti200, and a Geforce 4 MX is below that, so somewhere above a GeForce 3 range.