| >why did almost all of the RISC chips from the 1980s and 1990s fail? Citation needed. >Why aren't we using them today? Because we are using better chips made recently, not the ones from the 80s and 90s. >Why are Amazon, Google, and Microsoft buying an enormous number of x64 chips? Because performance vs cost in the current market, as well as access to x86 software moat. But this is changing. Notably, Amazon has Graviton, Microsoft was Windows for ARM with grease for x86 software, and Google has a digital design team, which is already iterating RISC-V based accelerators. Facebook, FAANG you have not mentioned, has its own RISC-V server effort. >I don't think instruction set really matters that much And yet, you're writing this very opinionated comment about ISAs. >RISC was a great idea Yes, it was. This is why the industry did never again make a tabula rasa CISC ISA. >At this point, RISC's proponents had to start explaining why a better instruction set did not translate into a faster chip. The RISC chips actually were faster. But this did not matter, as Intel had the better fabs, and the cash. So Intel was able bruteforce its way into enough performance for cheap enough that the market would then not bother going through the pain of switching ISAs. >without supplying better chips. The chips were better despite Intel's fab advantage. But they were not cheaper, nor did it run the software the market wanted to run. They sure sold these Pentiums, and were able to buy (and kill) Alpha later. The one and only reason x86 survives to date is this software moat. This moat advantage is in danger now, thanks to Microsoft's efforts to detach Windows from x86 and provide emulation to handle the transition like Apple did. |
- ARM (ARM) - ARM has done very well. It traditionally focused on low power chips. Over the past two decades, ARM has created faster and faster chips. Its chips can now be used in laptop, desktop, and server systems. I would argue ARM is a success. I would also argue it's not clear that ARM systems are faster than Intel or AMD systems.
- Alpha (Digital Equipment / Compaq / Hewlett Packard) - Alpha is dead. No one makes or sells Alpha computers any more.
- MIPS / Silicon Graphics - Silicon Graphics is gone. MIPS may survive as an embedded chip. MIPS chips are not used in used in main stream servers nor do they out preform x86 chips from AMD or Intel.
- PA RISC (Hewlett Packard) - HP dropped this in favor of Intel's Itanium chips.
- POWER (IBM) - This architecture is still being sold by IBM in real products. My guess is it is a good chip but it is still more expensive and slower than chips from AMD and Intel. Still, IBM deserves a lot of credit for keeping POWER going for over 30 years and for outlasting all of the other server/workstation RISC chips from the 1980s and early 1990s (ARM was not in servers or workstations during this time period). One sign that POWER is slower than Intel and AMD is there are no POWER chip benchmark results for the integer speed tests on the SPEC web site (https://www.spec.org/cpu2017/results/cint2017.html). This implies that IBM's cores are slower than x86 cores.
- PowerPC (Motorola and IBM) - This may survive as an embedded chip. It is not used in servers or desktop/laptop computers. Apple was the only user and they switched to Intel in the 2000s (they also recently switched from Intel to their own custom ARM Mx chips).
- SPARC (Sun Microsystems) - The microprocessor design team radically downsized sometime in the last decade (https://www.networkworld.com/article/964265/the-sun-sets-on-...). It still has support but my guess is the chips are not fast or cheap. The only reason you would use it is if you had software you could not move to x86 or ARM systems.
We had 7 RISC chip architectures launch in 1980s and 1990s. 6 were used in workstations and servers. One (ARM) was primary used in low power systems in the 1990s. In 2024, 2 are still going (ARM and POWER), 1 is on life support (SPARC), 2 may be used in some embedded systems (MIPS and POWER PC), and 2 are dead (Alpha and PA RISC).
ARM chips may be able to outperform x86 chips but I have seen very little evidence of this (Apple's M1, M2, and M3 may be better but it is hard to tell without reliable independent benchmarks). POWER is probably a good chip but it has failed to beat x86's performance. The rest are irrelevant in the laptop, desktop, and server world.
My main point is RISC's proponents promised that RISC chips would be faster than CISC chips like the x86/x64 chips. In 2024, we have not seen any evidence that the fastest chip must be a RISC chip. In fact, we have seen the opposite where none of the RISC architecture's hold the undisputed performance crown. If RISC was better, at least one of the RISC chip designs would have defeated AMD/Intel by now.