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Static precautions:
Newer provides a disposable wrist strap and we recommend its use. I personally leave the power cord installed in the machine
to assure that the chassis ground is connected to a real earth ground (power strip OFF). Touching the power
supply metal housing will also assist in discharging any static charge before touching the
system or addin card.
Cable clearance:
In case you didn't read this note on the XLR8 review, on the PowerMac 8500
there is a ribbon cable that connects to the motherboard very close to the processor slot.
I recommend that you flex this cable away from the processor card connector to avoid contact
with the dip switch solder side pins on the CPU card.
Apple Memory Control Panel - Disk cache settings:
Disk scores were somewhat disappointing until I increased the Apple Disk cache
from the default of 96k, to 512k. This made a huge difference not only in MacBench
scores but in actual finder performance. I did not experiment with settings above 512k,
but contrary to what many experts say about leaving the 96k setting alone, this change
made a noticable difference in operational and benchmark speeds.
Bus Speed Adjustments:
The Newer card provides for bus speed settings from 40mhz ( not recommended ) to 60mhz.
We recommend you first install it at the default bus
setting and CPU speed. Most users will be content with the
performance increase this provides. Remember to
press the CPU reset switch when first installing the card to ensure
the new CPU will be recognized. With the Newer card, it was not necessary to do this when
changing speeds, and the location of the speed setting switch was very convenient . The manual from Newer (latest revision) has excellent instructions with pictures for the Powermac 7500, 8500, 9500 and most clones showing the installation procedure and reset switch locations for each machine. The Newer card consistently ran reliably at much higher bus speeds than any other card.
Apple L2 Cache limits:
If you have the stock Apple L2 cache, bus speeds beyond 45 or 50 mhz may not be possible.
(Update - 5/16/97 - check out the new Cache Crop page for more cache info)
However, the Newer card seems much more tolerant of cache than the XLR8 card was.
If in doubt that the L2 cache is the culprit ( most likely ), you can remove the L2
cache and retest. Unfortunately as all PM8500 owners know - the Apple case design
makes adding/removing memory or cache a 20 minute disassembly exercise.
The 7500 is much better in this respect as are the new PM 8600/9600 and most Mac clones.
OverClocking:
Newer provides at least one setting in the manual for overclocking the chip. In some
cases this requires the 60mhz bus speed, which may require moving dimms to
prevent interleaving according to user reports. Most Apple made PowerMac's will not be able to use that
bus speed setting, and only a few will run at the 56.25mhz bus speeds. Adding a quality L2 cache such as
the PowerLogix Rapidcache has allowed this speed on many User's Macs
we have been told via email. Adding a 1meg cache really helps performance on the faster CPU cards as well.
Bus Speed is Key to Performance:
Obviously, the highest performance overall will result from using the highest bus speed that runs reliably
in your system. The Scores page shows that even the CPU performance was better
at the 52.5/210 setting than at the lower bus/higher speed CPU setting of 45/225. Only the FPU score was
better at the 45/225 setting.
Installed hardware ( PCI cards, disks, etc. ) is another variable that can affect the maximum bus speed that your computer will sustain. It is critically important to ensure that the system is running reliably - be sure to verify that the system is stable with all your applications before "closing the case". Run the system for several hours to ensure that it is stable after operating temperatures have risen and stabilized. Performance without reliability is nothing but frustration.
Memory Interleaving:
If your motherboard supports it - always add dimms in pairs in the Ax/Bx slots. This
interleaving effectively makes the memory bus 128bits wide. This interleaving really
helps in the real world when you're "beating up" the processor, although true multi-tasking
OS's benefit the most. To see if your system is using interleaving - download the excellent
DayStar
Npower control panel. This control panel is a dream come true! Very impressive,
but I expected nothing less from the people who taught Apple about Multi-Processing
and processor upgrade design.
Note: Some owners have reported that they
had to stop interleaving memory (move dimms) to enable the cards to run at
the higher processor speeds ( above 200 mhz). We did not do this during our testing
as removing interleaving extracts a 5% to 15% performance
penalty (depending on who you talk to, and what app/benchmark you run). I personally
would not consider that a viable alternative. Why cut memory performance up to 15% to
gain another 10-15% in cpu speed?? This problem has been noted on several
web sites and appears to be related to only certain PM9500 systems ( not a common
problem). My opinion is these users should verify that all their memory is of similar type
and speed (at least in the matched pairs). Timing differences when two dimms from
different manufacturers are in the A/B slots could possibly cause the problem. (I do not believe
this problem is related to the Newer Technology boards.)
604 vs 604e:
In case you didn't know, another benefit of the 604e upgrades is the fact the
"e" has twice the internal CPU cache of previous models.
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