Re: Understanding iSeries Performance Positioning

["Nathan M. Andelin" <nandelin@xxxxxxxxxxxxxxxxxxx>]

Yes Leif.  I've run into some misleading numbers too.  Mhz is one of them.
The published Mhz of the 170-2290 is 200.  The published Mhz of the 270-2250
is 400.  But the benchmarked CPU speed of the 270-2250 is 17 times greater -
not 2 times greater.  I don't really want to stir up that can of worms, but
readers should beware about putting weight into Mhz.

I've also been doing some Net.Data and CGI benchmarking lately.  My results
seem to be completely different from those that are published in the iSeries
Performance Capabilities Guide.  But again, that guide doesn't offer any
specifics about the benchmarks they used.  My conclusion is that their tests
must have been extremely trivial as far as CPU bound logic is concerned.

Nathan.

> Since boxes may differ wildly in terms of (say)
> number of disk arms, it seems hard to compare
> just based on processor/feature codes.

> Seems to me that there is some voodoo going on.
> Some rather arbitrary numbers being floated around.
> With most other platforms the various benchmarks
> (as you point out) are more or less public, so some
> validation of the numbers is possible. The CPW is
> much harder to get a handle on.