What does it means that a MCU has support for OpenGL?
PowerPC 7410 CPU (from the PowerPC G4 family) is from 1999.

Graphics boards did not do any triangle point calculations yet, so for OpenGL 3D the CPU has to do a ton of matrix multiplications before handing the triangles/quads off to the gfx board.

The newly included SIMD instructions would accelerate this quite a bit. Other than that this is pure marketing speech.