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I believe that there is "1" ALU per core in a CPU correct? I seem to be having a little bit of difficulty looking this up. Someone asked me in a discussion for school so I am quite curious as well.

Duffman
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    This question appears to be off-topic because it is not about programming or development. See [What topics can I ask about here](http://stackoverflow.com/help/on-topic) in the Help Center. Perhaps [Super User](http://superuser.com/) or [Electrical Engineering Stack Exchange](http://electronics.stackexchange.com/) would be a better place to ask. – jww Mar 15 '15 at 03:38
  • @jww Perhaps help migrate this? Original asker, Can you please create an account on the latter? – 0fnt Mar 15 '15 at 03:40
  • @user247077 - I can't migrate a question (even my own). It has to be flagged for moderator attention. It is by design (for better or worse); see [What is migration and how does it work?](http://meta.stackexchange.com/q/10249/173448), [Could normal users have an easier way to flag for migration?](http://meta.stackexchange.com/q/109740/173448), [Add a direct link for a user-initiated migration?](http://meta.stackexchange.com/q/158994/173448), et al. – jww Mar 15 '15 at 03:45
  • 1:1 is not guaranteed - even the entire "ALU" designation does not hold in some modern CPU designs. – user2864740 Mar 15 '15 at 03:51

2 Answers2

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Modern superscalar (http://en.wikipedia.org/wiki/Superscalar) CPU has many execution pipelines, and there can be ALU in several pipelines. For example, Intel *Bridge microarchitecture has 6 execution ports; and some ports has 2 or 3 execution pipelines behind them; Haswell has 8 ports. Check http://www.anandtech.com/show/6355/intels-haswell-architecture/8 - it has picture of pipelines for Nehalem, Sandy Bridge and Haswell with some ALU marked (I count 6 ALU for Haswell; and there are many smaller ALUs in this billion sea of transistors)

There are also SIMD ALU common in current days (SSE2, AVX, ...); SIMD has several ALU to work on short vector.

osgx
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No, the number is very different across CPUs. Look up Superscalar on wikipedia for getting a feel and then some reference text to get started. Also, read up on Hyperthreading if you get around to that.

0fnt
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    Hyperthreading or any normal variant of SMT will not increase number of ALU; only AMD's "Modules" has separated integer pipelines... – osgx Mar 15 '15 at 03:40
  • @osgx I realize that, I figured it'll help him understand the utilization of ALU. Thanks for pointing out though. – 0fnt Mar 15 '15 at 04:26