2 or 4 processors?

[Charlie]

This should be easy -

Windows XP Pro supports "up to 2 symmetric multiprocessors".
Does that mean 2 processors or 4?

I always understood that NT/2K/XP Workstations could
support 2 processors. Today we received a high end XP Pro
workstation for a user who mistakenly believes he needs one
and when I look at either Device Manager or Task Manager,
they seem to display 4 processors.

I'm just looking for an explanation and wondering if this
is new to XP.

Thanks.

 

[Shadow of James]

Could this be support for 2 hyper-threading Pentium 4's. Some software will
recognize a single hyper-threading P4 as two seperate processors. Norton
smartweep is the on software in particular I had this happen with.

 

[Nathan McNulty]

If these are high end workstations, they are most likely on Dual Xeon
Processors which use HyperThreading Technology. This will show 4
Processors, but I do have a suggestion. Since most programs currently
don't support this many processors and will not take full advantage of
it, it may be best to turn off HyperThreading. This will actually turn
into a performance increase in programs that cannot utilize
HyperThreading and even some that can.

 

[Charlie]

Excellent!
First of all, I should have mentioned that they were Xeon
processors, so I'm sure you are correct that they are
using Hyperthreading. The person who posted the previous
thread was also thinking correctly in suggesting that they
are hyperthreading, though not P4's (Thanks!).
So not only did you answer my question correctly, but
you've given me additional helpful information about
disabling hyperthreading.
Charlie

 

[Nathan McNulty]

Not a problem. You may find it intesting that many more applications
these days are becoming HyperThreading aware in which case it makes it
advantageous to use HT. You will have to decide what works best for
your computer, but here are a couple of articles showing how things have
changed. Unfortunately, they use benchmarks instead of real life
applications. The problem with benchamarks are that they almost all can
use HT Technology unlike many software programs. It is interesting to
note the changes in the last two years:
First - http://www.2cpu.com/articles/43_1.html
Second - http://www.2cpu.com/articles/42_1.html

 

[John R Weiss]

Yes.

Could this be support for 2 hyper-threading Pentium 4's.

 

[Rufio]

I believe so . But it has to be used in conjuction with the right (also
supporting H/T) motherboard, O/S, Java RTE & application, in order to
actually support hyperthreading (I have a 3.0 P4, configured this way). BUT
I did see some benchmarks shown in the trade press, where the 2 logical CPU
configuration was (FRACTIONALLY) slower in certain tasks - not enough to be
noticeable though.

Most people probably can manage without, right now )