Archived from groups: alt.sys.pc-clone.dell (
More info?)
In article <5O5Ge.22122$iG6.21537@tornado.tampabay.rr.com>,
tomtoo@softhome.net says...
>
> "Leythos" <void@nowhere.lan> wrote in message
> news:MPG.1d52ad071db5558c989a7d@news-server.columbus.rr.com...
> > In article <ej5Ge.39537$t43.5731@tornado.tampabay.rr.com>,
> > tomtoo@softhome.net says...
> >>
> >> "Leythos" <void@nowhere.lan> wrote in message
> >> news:MPG.1d52a745eed9b7d0989a7b@news-server.columbus.rr.com...
> >> > In article <b90he19a6slojirgqa2afeqen1iiij8pqc@4ax.com>,
> >> > tomba_nospam_@pobox.com says...
> >> >> I'm in dispute with Dell. They offered, and I ordered, a 9100
> >> >> Pentium-D 3.0ghz system with hyperthreading (HT). The shipped system
> >> >> does not have hyperthreading, which I need to run multiple copies of a
> >> >> CPU-intensive application.
> >> >>
> >> >> They claim that multipe core capability (MCC), which the system has,
> >> >> is faster than hyperthreading.
> >> >>
> >> >> Is that right?
> >> >>
> >> >> Are HT and MCC mutually exclusive or can I have both?
> >> >>
> >> >> Thanks for any insights.
> >> >
> >> > If you really thing that HT will make that much of a difference then
> >> > you
> >> > may be mistaken: If your application is not properly threaded it won't
> >> > gain more than 5% from a HT CPU. If it's not properly threaded it won't
> >> > gain much benefit from a Dual CPU or Dual Core CPU - about 10% is all.
> >> >
> >> > Dual Core is faster than HT, and Dual CPU's are faster than Dual Core.
> >> >
> >> > --
> >> >
> >>
> >> Why would Dual CPUs be faster than a Dual Core CPU? The pathways between
> >> the CPUs would be faster in the Dual Core.
> >
> > Because nothing is shared between them - they have their own caches and
> > complete paths.
> >
>
> OK, I'll buy that, but why would separate CPUs be faster?
Unless I misunderstand, it's where certain parts of the data paths are
common, meaning that you can have Two execution units, but data to the
chip still comes in on the common pins between both, so, if you have a
motherboard with the right chipset and a well designed structure, you
get a screamer, but it's still got one path in and one path out that's
shared.
With a Dual CPU board, you have two complete paths, one for each, and
they are independent of each other.
I can see DC being faster in some instances than DP, but it's a lot like
the early Celeron CPU's where a Celeron 1ghz was faster than a non-
celeron 1ghz since the Celeron internal cache ran at 1ghz and the non-
celeron ran at 500mhz (half cpu speed) - in some instances the Celeron
would run applications faster due to their cache use.
When it comes to benchmarks, people will set them to take advantage of
DC so that it appears DC performs faster than DP, and the same for the
teams that want DP to look faster, the only way to know for sure is to
put the same speed CPU's in a box, with the same components (except
motherboards) and test something like SQL Server on 2003 and see how
well it performs.
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