/vr/ - Retro Games

>>3605440
>>3605520
N64's GPU (Reality Co-Processor) was fabbed on 350nm, which was relatively new at the time and I think that in 1995, only Intel could do it. So for 1996 it was still pretty damn cutting edge.

Sega would have been shown 600nm or even 800nm prototypes of RCP by Silicon Graphics. That would have been an absolutely enormous chip. RCP has a shitload of stuff crammed into it, it's pretty incredible what they even managed. Contrary to what seems to be popular belief, the N64's engineering was incredibly good - RCP is probably the first GPU ever produced to have T&L and rasterization on the single die.

Just look at this die photo. RCP has a memory controller, vector and scalar units for T&L, four sets of cache, a long rasterization/texturing pipeline crammed with features, and a video post-processing unit all on the one fucking die that isn't larger than a budget MIPS CPU. I'm honestly surprised this doesn't get more praise.

By the way, if RCP wasn't attached to a highly constrained memory system, its rasterization/texture pipeline would probably outperform the original 3dfx Voodoo by a small margin albeit with slightly lower quality bilinear filtering. SGI actually got the pixel pipeline running faster than 3dfx even though they needed to conform to low-cost console yields.

If you want to point the finger at why the N64 isn't kicking the Voodoo's ass, point it at Nintendo and their cheap as fuck memory subsystem.

>>3318416
Eh, RCP was decapped a while ago.

Still doesn't mean we know what these units do on a binary level.

>>3250062
It's not a separate chip, it's part of the GPU.

Pic is a die scan of the N64's GPU. The half labeled RSP is the T&L half which also processes sound. It's also the microcode programmable half.

The other half labeled RDP is the graphics fill half which is what actually draws the screen. Almost all of the time RDP would be the slower half, the weak link, since it has to do fuckloads of RMW (read modify write) operations for the z-buffer to work.