[pezezin]

> So, getting a much smaller CPU would have been a big corner to cut, that could have saved enough resources to increase the texture cache to a useful resolution like 128x128 or so.

How? The texture RAM (TMEM) is in the RSP, not in the CPU.

[indigo945]

How is that relevant? "Resources" really just means money, which can be allocated between different items on the BoM at-will. The N64's chips are all (more or less) bespoke, so the functionality of each individual part is completely under Nintendo's control. Spend less on the CPU, and you suddenly have money left to spend on the RSP. (And on the RDP, which contains the TMEM -- it lives on the same chip as the RSP, but is a distinct thing. I assume you know this, but just to add to the discussion for readers - the RSP is the N64's SIMD coprocessing unit, which most games use to perform vertex shading, whereas the RDP is the actual rasterization and texturing hardware.)

[mrguyorama]

Realistically it wasn't even "We only have X dollars to spend". They needed the console to have a final budget and they really could have "just" added more transistors dedicated to that texture unit without significantly altering prices or profit.

But hardware was actively transitioning and what we "knew" one year was gone the next and Nintendo was lucky to have made enough right choices to support enough good games to survive the transition. They just got some bets wrong and calculated some tradeoffs poorly.

For example, almost everything Kaze is showing off, all the optimizations were technically doable on original hardware, but devs were crunching to meet deadlines and nobody even thought to wonder whether "lets put a texture on this cube" needed another ten hours of engineering time to optimize. Cartridges needed to be constructed by Christmas. A lot of games made optimization tradeoffs that were just wrong, and didn't test them to find out. Like the HellDivers 2 game size issue.

Sega meanwhile flubbed the transition like four different ways and died. Now they have the blue hedgehog hooked up to a milking machine. Their various transition consoles are hilariously bad. "Our cpu and rasterizer can't actually do real polygon rendering and can't fake it fast enough to do 3D graphics anyway. Oh, well what about two of them?"

[pezezin]

You are right about the RSP/RDP distinction. My point is that removing transistors from one chip doesn't magically let you add more transistors to another chip, that's not how IC fabrication works. And the CPU was not a custom design, it was a VR4300 licensed by NEC from the original R4300.

Anyway, the real problem is that TMEM was not a hardware-managed cache, but a scratchpad RAM fully under the control of the programmer, which meant that the whole texture had to fit under a meagre 4 kB of RAM! It is the same mistake that Sony and IBM later made with the Cell.