[...] There's no space for extra 20+W of power consumption in a MacBook Pro. Which is why it has a modest 2GB VRAM. All desktop Radeon Pro series cards have 8GBs VRAM and they're the same chip as this one, but VRAM is cut down to conserve power consumption. Nothing is free.
And I claim there is power space for having 8GB VRAM in the MBP, the same I claim there's power space for >16GB RAM. Anyway, let's suppose there would really be an unbeatable limit imposed by the Laws of Physics. Fine, by Tim's Law, you can show why a MacBook Pro cannot hold more than 4GB VRAM nor 16GB RAM.
But then, you'd had a bad time trying to explain why Apple has also made it impossible to choose a decent GPU in Mac desktops. Only exception was the tower-based Mac Pro, but they realized it didn't agree to Tim's Law, so they "fixed" it.
The conclusion is clear. Apple does not (and I mean: not, or, in other words but equivalent: not) care anymore for the professional user. It's just Facebook users, web, iOS, and watches. That's their only worry. I don't work in those fields, so, no wonder Macs are no longer for me (except perhaps the Retina MacBook, as I just said in a previous post, whose performance limitations I consider very reasonable given its lightness, quietness, and beauty --I cannot say the same for the new MBP, sorry).
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