The NV2A is the northbridge of the chipset, as well as the GPU.
The GPU is part of the NV20 family (Kelvin):
|Code name||Official Name|
|NV20|| GeForce3 (Ti)|
|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
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.