oki for the last time...
TnL = Transform & Lighting
nShadow = nvidia Shadows
sShadow = Stencil Shadows
FP = Full Precision
HP = Half Precision
FF = Fixxed Function
HW_ = Hardware Support (Vertex/Fragment)
SW_ = Software Support
CD = Colour Depth
ZD = ZBuffer Depth
SD = Stencil Depth
GeForce256 - TnL, CD32 ZD24 SD0
GeForce2/2GTS/2mx/4mx - TnL, FF, sShadows, SW_2.0, FP16, CD32 ZD24 SD4
GeForce3 - TnL, FF, sShadows, SW_2.0 HW_1.1/1.3, FP16 NV20, CD64 ZD24 SD8
GeForce4ti - TnL, FF, sShadows nShadows(1), SW_2.0 SW_3.0 HW_1.1/1.4, FP16 NV20, CD64 ZD24 SD8
GeForceFX - TnL, FF, sShadows nShadows(6), SW_3.0 HW_2.0+/2.0+, FP32 HP16 NV20 NV30, CD128 ZD24 SD16
the FX5800 & FX5900 both have quite a few functions of thier own as well, but no need to worry about them unless your developing specifically.