Mac Pro processor "hobbled"?

Discussion in 'Mac Pro' started by DeadSirius, Nov 26, 2006.

  1. DeadSirius macrumors member

    Sep 16, 2006
    I have MenuMeters installed, so I can always watch my processor activity in the menu bar. It seems that processor #1 is less active than the other 3. Even when the system gets busy, and activity increases on the entire set, it seems that #1 is always a couple of notches lower than the rest. I run an eDonkey server around the clock, and it has a tendency to max out a random processor individually on a rotating basis, but #1 rarely seems to get chosen for one of these spikes.

    Hardware Test never complains about it, so I don't know if it's worth fussing about. Is there something special about the first processor that the System withholds it from regular usage?
  2. matticus008 macrumors 68040


    Jan 16, 2005
    Bay Area, CA
    I don't know specifically about the newest Intel architecture, but a number of Xeon servers I've managed in years past have attempted to keep load off the #1 CPU wherever possible, to allow for processes which can't span processors or can't recognize addresses beyond the first CPU.

    I was told by an engineer friend in the mid-90s who worked with SMP that the theory was like boarding an airplane: load from the back forward, except VIP processes, which get to go where they want, when they want.
  3. SmurfBoxMasta macrumors 65816


    Nov 24, 2005
    I'm only really here at night.
    In most SMP-aware apps (OS X) & multi-CPU systems (Mac Pro), CPU #1 is normally reserved for the OS and it's inherently complex operations of controlling everything that happens, and it assigns other, lower priority and/or less complex tasks to the rest of the available cpus.

    So yea, the OS is da VIP in this instance :)

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