Frequently Asked Questions - AOpen AP5TC User Manual

Frequently Asked Questions

Q: Why the AOpen mainboards (MB) do not have cache module
expansion slot?
A: Faster CPU speed requires more difficult and complex MB timing design.
Every trace and components delay must be taken into consideration. The
expansion cache slot design will cause 2 or 3ns delay in PBSRAM timing,
and the extended trace length to the cache module through the golden
finger will further delay the timing by 1 or 2ns. This may result in unreliable
system once the cache module and slot becomes worn. All AOpen MBs
support 512KB PBSRAM onboard. For better performance (around 3%
higher than 256KB), we strongly recommend you to use 512KB onboard.
Otherwise, reliable 256KB is better than unreliable 512KB with cache
module. AOpen is the first company to promote this concept since the
fourth quarter of 1995.
Q: What is FCC DoC (Declaration of Conformity)?
A: The DoC is new certification standard of FCC regulations. This new
standard allows DIY component (such as mainboard) to apply DoC label
separately without a shielding of housing. The rule to test mainboard for
DoC is to remove housing and test it with regulation 47 CFR 15.31. The
DoC test of mainboard is more difficult than traditional FCC test. If the
mainboard passes DoC test, that means it has very low EMI radiation and
you can use any kind of housing (even paper housing). Following is an
example of DoC label.
Q: Can SDRAM DIMM work together with FPM/EDO SIMM?
A: The FPM/EDO operate at 5V while SDRAM operates at 3.3V. The current
MB design provides different power to DIMM and SIMM but connects the
data bus together. If you combine SIMM and DIMM, the system will still
work fine; however, only temporarily. After a few months, the SDRAM 3.3V
data input will be damaged by 5V FPM/EDO data output line. Therefore,
we strongly NOT recommend DIMM and SIMM combined together. There
is one exception, if your SDRAM supports 5V tolerance (such as TI or
Samsung), which accepts 5V signal at 3.3V operating power, you can
combine them.
A-2
AP5T
Test To Comply
With FCC Standards
FOR HOME OR OFFICE USE