page_title: Nintendo 64 technical specifications
section_title: Reality Coprocessor
hierarchical_section_title: Nintendo 64 technical specifications / Reality Coprocessor
caption_attribution_description: English: RCP-NUS(R3000 custom) in Nintendo64(NUS-001(JPN),PCB:NUS-CPU-01). 日本語: Nintendo64に搭載されているRCP(R3000 カスタム)
context_section_description: Nintendo 64's graphics and audio duties are performed by the 64-bit SGI coprocessor, named the Reality Coprocessor, or RCP. The RCP is a 62.5 MHz chip split internally into two major components, the Reality Display Processor (RDP) and the Reality Signal Processor (RSP). Each area communicates with the other by way of a 128-bit internal data bus that provides 1.0 GB/s of bandwidth. The RSP is a MIPS R4000-based 128-bit integer vector processor. It is programmable through microcode, allowing the chip's functions to be significantly altered by each software title if necessary, to allow for different types of work, precision, and workloads. A number of microcodes were provided by Nintendo, while a few companies, such as Rare and Factor 5, would later develop their own microcodes. The RSP performs transform, clipping and lighting calculations, and triangle setup. The Reality Display Processor is primarily the Nintendo 64's pixel rasterizer, and also handles the console's Z-buffer compute.
  The RCP was developed by SGI's Nintendo Operations department, led by engineer Dr. Wei Yen (who later founded ArtX in 1997). The RCP was manufactured by NEC, using its 350 nm 3LM CMOS process, which NEC had introduced in 1994. The processor contains 2.6 million transistors manufactured using this process. The 160-pin processor has a die size of 81 mm², giving it a transistor density of over 32,000 per mm². Thermal dissipation is rated at 2.8 watts.
  Instead of a discrete sound processor, the RSP frequently performs audio functions, although the CPU can be tasked with this as well. It can play back most types of audio (dependent on software codecs) including uncompressed PCM, MP3, MIDI, and tracker music. The RSP is theoretically capable of a maximum of 100 channels of PCM at a time, but only in a case where all system resources are devoted to audio. It has a maximum sampling rate of 48 kHz with 16-bit audio. In practice, however, storage limitations caused by the ROM cartridge format limit the audio size and thus quality. Some game titles are designed for higher quality audio when storage expansions are available, as with F-Zero X Expansion Kit.
  The RDP performs rasterization, generating, from geometry, pixels to be filled before output to the display.
  The system RAM is connected to the RCP via a 562.5 MB/s bus, and the CPU via a 250 MB/s bus. Unfortunately, there is no direct memory access through both these links and the RSP must arbitrate accesses. The RCP, like the CPU, is passively cooled by an aluminum heatspreader that makes contact with a steel heat sink above.
caption: RCP-NUS "Reality Coprocessor"
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