...
>about adding another processor to our 995/300.  our hp se pointed out that we
>*might* see a 10-15% performance gain if we did that.  he explained it
this way
>-- you can pretty much assume that one processor will be doing nothing than
>trying to manage the other three <sigh>                     - d
...

HP has a habit of understating (offering worst case) performance numbers.
Your SE might have taken the following into account (or not).

Adding a processor or two greatly can enhance performance; if no other
bottleneck is occurring or close and your application(s) mix can use the
extra CPU.

A) CPU
One processor did have a very small overhead for management in a
multiprocessor system. The overhead had little effect on overall
performance. Most processes, that could run, did run on the next available
processor. The important part is that other processes are ready for execution.

If you have a single job, with a single process occurring at a time, no
performance benefit will be seen.

If you have multiple processes, whether or not from the same job/session,
that can be scheduled at the same time; then you will see a good
performance increase.

B) IO
As most processes are dealing with data on disks, if you have a limited
number of spindles, then a smaller performance increase will be seen.

Spindle:

1) Mirrored Disks
   If the processes are mostly READING - each physical disk can be counted
as a spindle.
   If the processes are mostly WRITING - the mirrored disk pairs will be a
spindle.

2) RAID
   I have no useful experience and will leave this to others.

3) Standard Volumes
   More small drives (LDEVs) are better than fewer large drives.

If you have a lot of IO to other devices, then the process will give up the
CPU quickly. Performance increases will be seen if you have a LOT of these
IO intensive processes waiting.

C) MEMORY
More memory will not hurt. To little memory will cause swapping to disk.
Memory needs will be greater if the processes are running different NMPRG
files.

----

If you have a performance issue, invest in a performance monitoring tool
(Glance/SOS) and watch the system when problems are reported.  See if any
of the things mentioned above fit.

neal
800-682-0200
<http://www.minisoft.com>