Re: [tlug] CPU speed: reported vs. actual

["Stephen J. Turnbull" <turnbull@example.com>]

Darren Cook writes:

 > I'd think this meant I was now running at 900Mhz, and was actually
 > running at 1.7Ghz before, except Intel's own specs [1] say I should be
 > getting 27 GFLOPS.

No, Intel's own specs say *they* can get 27 GFLOPS.  It doesn't say
whether this is theoretical or empirical, let alone whether any actual
work is being done or if they simply ran an assembly program that
initializes a FPU register to 0.0 and adds some tiny number to it
repeatedly, and it explicitly disclaims *any* responsibility for what
*you* get:

    All GFLOPS, CTP and APP calculations contained herein were based
    on specifications taken from Intel datasheets and are subject to
    change without notice. Intel makes no representation or warranty
    as to the accuracy or reliability of such specifications. THESE
    CALCULATIONS ARE PROVIDED "AS IS" WITH NO WARRANTIES WHATSOEVER,
    INCLUDING ANY WARRANTY OF MERCHANTABILITY, NONINFRINGEMENT,
    FITNESS FOR ANY PARTICULAR PURPOSE OR ANY WARRANTY OTHERWISE
    ARISING OUT OF ANY PROPOSAL, SPECIFICATION OR SAMPLE. Intel
    disclaims all liability, including liability for infringement of
    any proprietary rights, relating to use of information in these
    calculations.
    <http://www.intel.com/support/processors/sb/cs-017346.htm>

Your first post says that on LINPACK you're getting 40% of what Intel
claims.  My bet is on "stop wasting your time worrying about whether
your CPUs are wasting their time". ;-)  Just which weather bureau or
nuclear weapons lab do you work for, anyway? :-)