• ARM, which formerly stood for Advanced (or Acorn) RISC Machine, is by far the most common non-x86 CPU architecture. It's a RISC ISA that dates back to the mid-1980s and is currently the king of embedded SoCs. It's in basically every smartphone and most tablets, and Apple is midway through transitioning their x86 Macs over to their own Apple Silicon ARM platform. ARM has most of the mobile space, and is emerging into the desktop space thanks to Apple and into the server space from companies such as Marvell and Ampere Computing.
  
• RISC-V is an open-source, constantly evolving ISA that anyone (with sufficient fabrication capabilities) can implement, manufacture, and market CPUs for. It's only been truly "stable" for a few years now so it's still a newcomer in all spaces, but offerings from companies like SiFive (who freely lets you design and test custom RISC-V cores based on their core IP in their online designer tool) are putting actual working RISC-V boards in the hands of developers and consumers through their own channels as well as through third parties such as the BeagleBoard.org project.
  
• MIPS is another 80s RISC design that is still getting updated (the latest release of the MIPS64 ISA spec is from 2014). I don't know much about what MIPS is used for other than in a number of deeply embedded situations such as small networking appliances (Ubiquiti's routers are MIPS-based, for example), but it seems cool!
  
• PowerPC is a RISC architecture from IBM that evolved from their original POWER RISC machines and eventually supplanted the original POWER ISA before confusingly being renamed "Power ISA". Everyone, including IBM, still calls it PowerPC though. Apple used PowerPC from the mid-90s through the mid-2000s, the seventh generation game consoles used custom PowerPC CPUs, and a bunch of modern satellites still use PowerPC because fairly speedy radiation-hardened PowerPC chips are a thing that works quite well, apparently.
  

• SPARC was Sun's RISC that replaced the Motorola 68000 family in their line of Unix (SunOS) workstations and servers. It also ended up in a few non-Sun products, such as Tadpole's SPARCbook series of laptops in the mid-late 90s. It's pretty much dead now, but you can still find relatively decade-old SPARC gear for not a lot of money on eBay. SPARC was originally a 32-bit architecture, but SPARC64 (formally SPARC V9) was introduced in 1993, so pretty much any SPARC machine you get that isn't proper vintage kit is going to be a 64-bit RISC machine. Linux and the BSDs all maintain up to date 64-bit SPARC ports.
  
• VAX was a CISC architecture minicomputer that replaced DEC's venerable PDP-11 minicomputer series by taking the same general ISA theory and extending it to 32 bits with full baked in support for virtual memory management and privilege levels (thus the name, Virtual Address eXtension). If you find a working VAX, I will quite envious of you, but not of your power bill.
  
• Motorola's 68000 (m68k) family was a microcomputer-focused CISC family that is notable for being the CPU that powered the first decade and a half of Macintosh computers. 68k machines are pretty much a curiosity at this point.
  
• I don't know nearly enough about PA-RISC, NS32k, Alpha, or Super-H to talk about them.
  

Kazinsal fucked around with this message at 11:22 on Jul 8, 2023