The G4 is a 32-bit processor. It's Altivec hardware can operate on
"128bits worth" of data at once, not actual 128bit data (it's just 4x32bit
chunks). But that portion is 128-bit. But it's nothing you will ever truly notice.

Actually to be more specific. The G4 PPC has 32 bit Interger units. Has a 64-bit Floating Point unit. And has 128 bit AltiVec (Velocity Engine) units..

And even if the chip was a true 64-bit like the Alphas unless you're doing super database crunching you'd never notice a difference.

I will note when it comes to games, pretty much every developer on the planet uses interger math, not floating point.

And if that LCD display is rated at only 300-nit before the Touchscreen, then you're gonna have a hard time seeing that in the interior of the VX during the day!