NV2A

The NV2A is the northbridge of the chipset, as well as the GPU.

XGPU (1.0)

XGPU S (1.1-1.4)

XGPU-B (1.6)

GPU

The GPU is part of the NV20 family (Kelvin)[1]:

Code name	Official Name
NV20	GeForce3 (Ti) Quadro DCC
NV25	GeForce4 Ti 4200, Ti 4400, Ti 4600 Quadro4 700 XGL, 750 XGL, 900 XGL
NV28	GeForce4 Ti 4200-8X, Ti 4800 (SE), 4200 Go Quadro4 780 XGL, 980 XGL
NV2A	Xbox GPU

Known Revisions

There are 3 known revisions of the Xbox GPU (XGPU), and they are as follows.

XGPU - Found on boards of revision 1.0
XGPU S - Found on boards of revision 1.1-1.4
XGPU-B - Found on boards of revision 1.6

There is very little known about the difference between the revisions, or why there had to be consecutive revisions.
It is unknown if they are pin compatible with each other.

Notes

• NV30 information and emulator
• List of implemented GL extensions for NV10-NV30: "NVIDIA OpenGL Extension Specifications for the CineFX Architecture (NV3x)", 13 Nov. 2006