Relative CPU performance tables show a 948 and 918 and 917 thru 947 as having
approximately the same CPU performance.  The 9x7 and 918 could (do) have a
floating point processor that can bring their performance to a little above
a 948.

But Memory capacity is generally greater on the later machines and can
have dramatic effects on overall system performance.

More importantly is the types and number of discs on your system.
All these systems typically have discs internal to the CPU.  Discs inside
a 9x7 and 918 are probably bigger and faster than those in the older 948.
The internal 948 discs would not be moveable to the other CPU's.

If you have discs outside of the CPU box, then the costs of new interfaces
or conversion interfaces must be considered.  You may be looking at
getting newer discs (FW or SE SCSI rather than FL's or HPIB) because of
IO slot restrictions and lower costs for fewer IO interfaces.

Of course, the newer systems generally have an internal DDS drive of a
later generation than the 948.  Look for at least a dds-1 with compression;
get a DDS-3 if possible (Please no DDS/DLT wars :))

The other major factor will be the Tier for the CPU.  Sorry but I do not
have info on that for HP or 3rd Party software.  This can be the Clinker ($)
for many cpu upgrades.

If you are looking at getting a bit more CPU power, then a 957 or 928 would
be about 50 and 40 percent faster.  As others have said, the 9x7's are nearing
their end-of-support life but spares and 3rd party support can be cheaper
on the used market than a new 918/928.  Only you know your tolerance for
outages and money constraints.

A leap to the 929 would be best for the longer term and would be about as
fast as a 977 or 978.  FW and SE SCSI are supported and FL and HPIB
also work if you insist on dragging old peripherals along.  Your programmers
will love it and there is an extensive CPU upgrade range available.

James (getting rid of my 980's for the same reason) Overman  HP CS R&D
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