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To be completely honest, MIPS CPU's had never been known for their speed – not until the release of the 64-bit MIPS architecture anyway when they finally became

To be completely honest, MIPS CPU's had never been known for their speed – not until the release of the 64-bit MIPS architecture anyway when they finally became competitive with other RISC CPU's, but it was a complete ISA redesign. Sun was in a somewhat similar boat with the SPARC v8 architecture, and they were rather late with UltraSPARC (SPARC v9 ISA). Yet, they managed to hold out longer due to having a switched memory controller and a very wide memory bus, which allowed them to become the best hardware appliance to run the Oracle database (despite being less performant), and divert the cash flow into the UltraSPARC development. UltraSPARC I was underwhelming, and with UltraSPARC II they finally caught up with other RISC vendors and gradually started outperforming some (e.g. MIPS) in some areas. Amusingly, the 512-bit wide memory bus has made a comeback in Apple M1 Max laptops (laptops!), and M1 Ultra has a 1024-bit wide memory bus. Why HP went all in with ditching their own perfectly fine PA-RISC 2.0 architecture is an enigma to me tho.

jojobas 4y ago
> Why HP went all in with ditching their own perfectly fine PA-RISC 2.0 architecture Again, thanks Rick Belluzzo.
hulitu 4y ago
> To be completely honest, MIPS CPU's had never been known for their speed SPEC would like to dissagree with you.
- jojobas 4y ago
  He has MIPS as not known for their speed and SPARC getting ahead as a major achievement in the same post.
  - inkyoto 4y ago
    That is a very frivolous interpretation of what I said. I was comparing: a) 32-bit MIPS CPU's with 64-bit MIPS CPU's, b) 32-bit SPARC v8 and 64-bit SPARC v9 (UltraSPARC) CPU's, and c) performance of 32-bit RISC CPU's comparatively to each other. 32-bit MIPS and SPARC v8 CPU's were slow, with MIPS32 being one of the slowest across the entire board. I was not comparing MIPS64 to UltraSPARC II or III because MIPS64 implementations (especially R10k and R12k) were exceptionally highly performant, especially in numeric computations that UltraSPARC CPU's were not known for at the time. UltraSPARC II/III systems were renowned for very high, sustained overall system throughput, and nor for high CPU computational performance. At the time, if one wanted a number crunching beast, they had a choice of either MIPS64, or PA-RISC 2.0, or POWER CPU's. Mostly either MIPS64 or PA-RISC 2.0 (I am not including DEC Alpha – another early performance contender – because it perished too prematurely in the acrid belly of Compaq/HP acquisition shenanigans and did not get a chance to advance past 21264).
- inkyoto 4y ago
  To be crystal clear: my statement pertained to 32-bit MIPS CPU's and MIPS CPU's predating the R8000. They were very slow. 32-bit MIPS CPU's did not have multiply and division instructions, they had branch delay slots that are unwieldy for a compiler to generate the efficient code for, plus other stuff. Early 32-bit MIPS implementations did not even have a hardware TLB (it was implemented in the kernel), which made the context switching between kernel and user spaces slow. R8000 (MIPS IV) was fast and later MIPS64 CPU's were very fast, especially on floating point operations, and consistently outperformed competing 64-bit RISC and x86 CPU's because the MIPS64 was an ISA redesign that addressed and fixed many of the problems of the 32-bit version of the ISA.

jojobas 4y ago

> Why HP went all in with ditching their own perfectly fine PA-RISC 2.0 architecture Again, thanks Rick Belluzzo.

hulitu 4y ago

> To be completely honest, MIPS CPU's had never been known for their speed SPEC would like to dissagree with you.

jojobas 4y ago
He has MIPS as not known for their speed and SPARC getting ahead as a major achievement in the same post.
- inkyoto 4y ago
  That is a very frivolous interpretation of what I said. I was comparing: a) 32-bit MIPS CPU's with 64-bit MIPS CPU's, b) 32-bit SPARC v8 and 64-bit SPARC v9 (UltraSPARC) CPU's, and c) performance of 32-bit RISC CPU's comparatively to each other. 32-bit MIPS and SPARC v8 CPU's were slow, with MIPS32 being one of the slowest across the entire board. I was not comparing MIPS64 to UltraSPARC II or III because MIPS64 implementations (especially R10k and R12k) were exceptionally highly performant, especially in numeric computations that UltraSPARC CPU's were not known for at the time. UltraSPARC II/III systems were renowned for very high, sustained overall system throughput, and nor for high CPU computational performance. At the time, if one wanted a number crunching beast, they had a choice of either MIPS64, or PA-RISC 2.0, or POWER CPU's. Mostly either MIPS64 or PA-RISC 2.0 (I am not including DEC Alpha – another early performance contender – because it perished too prematurely in the acrid belly of Compaq/HP acquisition shenanigans and did not get a chance to advance past 21264).
inkyoto 4y ago
To be crystal clear: my statement pertained to 32-bit MIPS CPU's and MIPS CPU's predating the R8000. They were very slow. 32-bit MIPS CPU's did not have multiply and division instructions, they had branch delay slots that are unwieldy for a compiler to generate the efficient code for, plus other stuff. Early 32-bit MIPS implementations did not even have a hardware TLB (it was implemented in the kernel), which made the context switching between kernel and user spaces slow. R8000 (MIPS IV) was fast and later MIPS64 CPU's were very fast, especially on floating point operations, and consistently outperformed competing 64-bit RISC and x86 CPU's because the MIPS64 was an ISA redesign that addressed and fixed many of the problems of the 32-bit version of the ISA.