Miscellaneous Performance Notes
• Many factors effect the performance of the CPU card.
using high quality expansion products, cables and RAM
will ensure that you have a system that can perform much
faster with a “tuned” MACh Speed upgrade.
• Any speed can be set for any CPU, but a CPU will gener-
ally only operate at 20% more than its manufacturer rated
speed.
• Most of the logic boards supported by the MACh Speed
have a maximum Bus Speed of around 50 MHz.
• The CPU operating speed and the cache operating speed
are linked by the BUS speed on the card. The final oper-
ating speed of each is determined by the its Ratio to the
card’s BUS speed.
• CPU operating clock speed is determined by:
BUS Ratio X BUS Speed = CPU speed in MHz.
• Once the MACh Speed G3 Upgrade Card is installed, the
Motherboard Level 2 cache becomes a Level 3 cache.
Since the Motherboard cache is smaller than the Level 2
cache, it will not add to the system performance. If possi-
ble (as in the 8500/7500), you should remove the mother-
board cache.
Chapter 4 - Advanced Perf o rmance Tu n i n g
Page 5 9
2. Uncheck automatic startup of the cache.
• To avoid having problems with boot-up if you select “too
fast” of a setting, deselect the “Enable backside cache at
startup box”. You can enable automatic start-up later
once you have found the optimum setting.
3. Select “Advanced Options:
• Set the Cache control to the next highest Ratio. some set-
tings are not available for some card as the setting would
result in speeds much too high for the cache.
• Select “OK”
Setting the Cache Ratio for Maximum speed
4. Restart the backside cache
• In the main window, select “Enable Now”
• If you freeze at this point, then you have selected too fast
of a setting for your backside cache. It is possible to adjust
the CPU settings on the card to a slower setting, then
using a higher ratio on the backside cache.
• Your system should be able to run memory tests such as
TechTool Pro or DayStar’s PowerControl Testing software
overnight consistently to operate at the higher speeds.
Chapter 4 - Advanced Perf o rmance Tu n i n g
Page 5 8
