From an evaluation by Roy Longbottom, this interesting observation:
In 1978, the Cray 1 supercomputer cost $7 Million, weighed 10,500 pounds and had a 115 kilowatt power supply. It was, by far, the fastest computer in the world. The Raspberry Pi costs around $70 (CPU board, case, power supply, SD card), weighs a few ounces, uses a 5 watt power supply and is more than 4.5 times faster than the Cray 1.
There's this back story about the "LoongArch instruction system, a RISC ISA that blends ideas from MIPS and RISC-V". The article says it is MIPS-compatible and even runs the same Linux code [Loongson's] old MIPS-based CPUs did. Why not just use RISC-V? MIPS is licensed from the USA. I guess they have a lot of legacy people at Loongson.