Geforce 9800GT supports Hybrid Power

Geforce 9800GTX is, as you know, based on the same chip as Geforce 8800GTS and 8800GT and, together with 9800GX2, it's a high performance card that supports this power-saving feature.

Geforce 9 means Hybrid Power support, but please don’t forget that for such a card you need a board that supports it, and so far only Nforce 780a that supports Phenom, Athlon and Hybrid Power is out. An Intel alternative is yet to be launched.