Re: Dual processor PIII 866 versus single Pentium 1.4Ghz
Dunno about expert, but I have some experience in this area. The P4,
having a long pipeline, is more suited to streaming type processing: the
pipeline has to be 'full' before it'll give peak performance. I think
that most of the s/w that supports the new clever bits in the P4 are
benchmarking packages - not much 'real' software uses the new stuff yet,
and that's why it tends to be slower.
Think about what your application does: is it processing data i.e.
analysing/generating new data, or is it mainly data storage and
retrieval i.e. database or web hosting etc. If it's analysis type work
then the processor performance could have more impact whereas data
storage/retrieval is mostly about moving data around and unless you can
keep all your data in memory then you'll be held up by the disks.
(If it's an analysis etc. type package, does it support MP?)
Tuning the software to suit the utilisation will probably give a greater
performance increase than the difference between the processors you
mention, although currently I'd plump for the dual PIII. If dual
Athlons were available, for a reasonable price, I'd choose them. The
Athlon MP chipset has been released, I believe, but there may be some
issues with the special 460W psu that's required (not sure if you can
get them yet).
SCSI, in theory, requires less cpu overhead than IDE (I've seen some
scsi stuff giving horrendous cpu utilisation - usually a sign
something's wrong though), and supports more devices. Different
variations give different performance and different number of devices
supported per channel.
Does the AIC-7899 do h/w RAID? anyway, with only two HDs you can only
mirror them. Fortunately, s/w mirroring should require less overhead
than the other RAID schemes.
HTH
LeeE
mdevin@ozemail.com.au wrote:
>
> This is not a debian specific question, but I know there are some
> hardware experts out there that may be able to help me and I would much
> appreciate it :-)
>
> I am considering upgrading our server at work. I don't fully appreciate
> the performance advantage / disadvantages of dual processors and SCSI
> hardisks.
>
> Here is what I have been recommended to get:
> 2x Intel Pentium III 866 Mhz
> Intel TUPELO (STL2) Motherboard Dual Processor capable
> Adaptec AIC-7899 dual channel SCSI controller
> 2x 512 Mb Intel Certified ECC Registered Memory
> 2x Cheetah Seagate 36Gb LVD Hard Disks
> + network cards, floppy, CDROM, etc.
>
> Basically, my question is: What would the difference in performance be
> between this configuration versus say a single P4 1.4Ghz?
>
> This server will unfortunately have to run Windows NT (as the
> proprietary software requires it). It is basically a database server
> with 8x 486s acting as essentially dumb terminals. They will run a
> basic version of the proprietary software and all the processing will be
> done by the server.
>
> 1. What do people think about whether it is worth spending the extra
> money for dual processors? Does Win NT fully utilise dual processors?
> It is nearly $1500 (Aus) for the motherboard! But a P4 1.4 GHz is much
> the same price (I think), but the mother board would be cheaper then.
>
> 2. Is it worth spending the extra money on a SCSI controller and hard
> disks?
>
> Here is what the specs say on the SCSI HD:
> Formatted Capacity: 36.4GB
> Interface: 68-pin
> Ultra2/SCSI
> Data Transfer Rates: 160MB/s
> Average Seek Times: 5.4ms
> Buffer Size: 16MB
> Rotational Speed: 10000rpm
> Height (inch/mm): LP (1.0/25.4)
>
> Here is the specs on a 40Gb Western Digital IDE 7200 RPM:
> WD CaviarTM 40GB EIDE Hard Drive WD400BB
> Transfer mode: 100 MB/s
> Average Read seek: 8.9ms
>
> So the SCSI spins faster and has lower average access times. I suppose
> this means that it would be of benefit when you are talking about a
> large database server with multiple terminals connected.
>
> It is just hard to work all this out from the specs. Can anyone speak
> from experience on these issues? Especially regarding the dual
> processor versus single but faster processor.
>
> Thanks for help.
> Mark.
>
> --
> To UNSUBSCRIBE, email to debian-user-request@lists.debian.org
> with a subject of "unsubscribe". Trouble? Contact listmaster@lists.debian.org
--
http://www.spatial.freeserve.co.uk
Reply to: