4 ms·
> Then CISC microprocessors became superscalar, and started executing more than one instruction per clock. Now RISC machines were behind in speed. So they had t
by nordsieck 4y ago
> Then CISC microprocessors became superscalar, and started executing more than one instruction per clock. Now RISC machines were behind in speed. So they had to become superscalar. That killed the simplicity. There was no longer any real point to pure RISC instruction sets.
I thought DEC Alpha was always ahead in speed. At least until it got bought and mostly abandoned by Compaq and then HP. Or is Alpha insufficiently RISC?
- msla 4y agoThe Alpha was RISC, and, as seen in page 14 of this very long, very interesting set of slides, it eventually got passed in raw MHz by x86 chips (specifically, the 1 GHz AMD Athlon vs the 667 MHz Alpha 21164 around the year 2000) but you can see it was a close race https://users.nik.uni-obuda.hu/sima/letoltes/Processor_families_Knowledge_Base_2019/Intels_Itanium_(IA64)_family_2018_10_29.pdf https://users.nik.uni-obuda.hu/sima/letoltes/Processor_famil... This PDF shows the Alpha 21164 was superscalar: https://acg.cis.upenn.edu/milom/cis501-Fall09/papers/Alpha21164.pdf https://acg.cis.upenn.edu/milom/cis501-Fall09/papers/Alpha21...
- nordsieck 4y agoWhile that's true, it still retained a performance advantage in floating point[1]. And that's after 2 years of neglect after being sold to Compaq. --- 1. https://www.realworldtech.com/battle64/ https://www.realworldtech.com/battle64/