Re: [gentoo-user] new machine : CPU : 22 nm vs 32 nm

[Volker Armin Hemmann]

Am Mittwoch, 25. Juli 2012, 16:24:42 schrieb Philip Webb:
> 120725 Volker Armin Hemmann wrote:
> > Am Mittwoch, 25. Juli 2012, 16:05:29 schrieb Philip Webb:
> >> I've listed what's available at the local store,
> >> which I trust to stock reliable items, tho' I wouldn't ask their advice.
> >> All the AMD's are  32 nm , while the Intel recommended by one commenter
> >> -- Core i5-3570 4-Core Socket LGA1155, 3.4 Ghz, 6MB L3 Cache, 22 nm --
> >> is  22 nm : it costs  CAD 230  & they have  3  in stock,
> >> which suggests demand, but not the most popular ( 9  in stock).
> >> Isn't  22 nm  going to be faster than  32 nm  ?
> >
> > no
>
> In the absence of further explication, I'm likely to go with  22 nm .

because structure size has no influence on the performance - from a user point 
of view.

In theory: smaller structers - less power needed - faster switching - so 
higher clocks are possible.,

In practice: smaller structures - more leak current - not as much faster 
clocks as hoped.

For a user there is no difference between a 3ghz 32nm or a 3ghz 22nm cpu. The 
later one MIGHT use less power. But nothing is guaranteed.

>
> >> In the same price range, AMD offers  Bulldozer X8 FX-8150 (125W)
> >>
> >>  8-Core Socket AM3+, 3.6 GHz, 8Mb Cache, 32 nm  ( CAD 220 ,  2  in
> >>  stock).
> >>
> >> How do you compare cores vs nm ?
> >
> > who cares?
>
> These answers are not very helpful : does anyone have anything  more so ?

because you don't. cores and nm are in no way related.

>
> >> How far is cache size important ( 6 vs 8 MB )?
> >
> > depends on the architecture.
>
> It occurs to me that a larger cache goes with more cores,
> so the last question is not so important.

no, really, this is the only question that makes sense.

And it depends on the cache structure. A 6mb L3 'victim' cache that only 
caches stuff that is not in L2 and L1 might be better than a 8mb L3 cache that 
also holds the same stuff as L2 and L1.

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