When to pick quad core and when to pick dual core

Discussion in 'NZ Computing' started by thingy, Nov 20, 2006.

  1. thingy

    thingy Guest

    Hi,

    When considering a server purchase....

    The Q is, is 4 x 3 GHZ Xeons (12Ghz overall) with 2 x dual core CPUs
    better or 8 x 1.86 Ghz or (14Ghz) CPUs better via 2 x quad core CPUs.
    This really depends on how well an application scales on multiple CPUs
    and the effects of the different cache sizes available v raw GHZ....or
    combinations thereof.

    Anybody found some good articles out there for server applications,
    especially sendmail?

    Trying to decide which CPU to buy....

    regards

    Thing
     
    thingy, Nov 20, 2006
    #1
    1. Advertisements

  2. thingy

    Who Am I Guest

    Well for the Quad Core machine we ended up buying Macs because they were
    cheaper than the local PC supplier by about $1000 a machine..... and
    that is to run them as linux boxes so we were not factoring in Windows
    as a cost on the machines but the Macs do include OSX.
     
    Who Am I, Nov 20, 2006
    #2
    1. Advertisements

  3. thingy

    thingy Guest

    Same server but with different cpus, rather than a different piece of
    kit....looks like quad core does little for Sendmail so dual cores seems
    the better option....surprisingly hard to find real information and not
    hype out there...

    regards

    Thing
     
    thingy, Nov 20, 2006
    #3
  4. thingy

    Tony Guest

    Sendmail doesn't use that much CPU, but memory and disk speed will be
    important. I would tend to pick the more modern quad cores and put in
    crap loads of memory over the older 3gig Xeons. Remember, the MHz rating
    does not necessarily equate to processing power. SAS drives in a raid 10
    (plus hot spares if you can) if you want exceptional speed as well.
     
    Tony, Nov 20, 2006
    #4
  5. thingy

    Who Am I Guest

    Same server but with different cpus, rather than a different piece of
    kit....looks like quad core does little for Sendmail so dual cores seems
    the better option....surprisingly hard to find real information and not
    hype out there...

    regards

    Thing[/QUOTE]

    We got them for number crunching x-ray data.
    Performance of any app will depend on the level of multi-threading and
    how well the threads can be distributed across multiple CPUs.
     
    Who Am I, Nov 20, 2006
    #5
  6. thingy

    thingy Guest

    yep, already specified 16gig....contemplating the drives still, might
    get 4 x 73s, 2 in a raid 1 for /var/spool/mqueue and 2 for the
    rest....that way I split logging and the mail queue....however they say
    the mail queue is best served by a raid5 for fast reads (makes
    sense)....which means 3 disks, so a 5 disk+ chassis which means a Dell
    2950 and not a 1950....(which only holds 4). I am looking at the disk
    i/o at the moment on the old box to see if the present setup is doing
    Ok, so far the aforementioned 4 disk setup looks OK.

    I find it interesting that most people only think of disks in terms of
    capacity....like I often have discussions with people who say "why do
    you need more disks? 2 x 300 gig is heaps of space!!!" I am having bun
    fights over these and proxy servers....and if I want to go up a chassis
    size (from 1U to 2U) I also have to go through agro....

    Then there is the SAN, we got a "product" to "reclaim space" So at
    present we are running over multiple 8+1 R5s. So now the expectation is
    that we will recover some of this for "other use". Of course cutting the
    disk numbers by half means a huge hit on the disk i/o capability.....

    :/

    regards

    Thing
     
    thingy, Nov 20, 2006
    #6
  7. A friend of mine mentioned using DRBD to continuously mirror the mail queue
    across two physically separate machines. They were able to do a server
    upgrade by forcing a failover from the old machine to the new one.
     
    Lawrence D'Oliveiro, Nov 21, 2006
    #7
    1. Advertisements

Ask a Question

Want to reply to this thread or ask your own question?

You'll need to choose a username for the site, which only take a couple of moments (here). After that, you can post your question and our members will help you out.