User`s guide

Frequently Asked Questions
B-11
4.00.950B OEM Service Release 2 or OEM Service Release 2.1
If you are running OSR 2.1, you may tell it from by check ing "USB
Supplement to OSR2" in the list of installed program of Add/Remove
program tool under Control Panel, and checking for version 4.03.1212 of the
Ntkern.vxd file in the Windows\System\Vmm32 folder.
Q: What is the difference between AX5T-1 and AX5T-2?
A: AX5T-2 fixes the ATX power supply to off state when you first time install
your AX5T mainboard. AX5T-1 can be probably on or off. Note that currently,
they all have 75MHz but without 83.3Mhz jumper setting because of clock
generator limitation. The user set clock to 75MHz is taking his own risk, and
is probably to have system unstable behavior.
Item AX5T-2 AX5T-1
75MHz jumper setting Yes Yes
83.3MHz jumper setting No No
ATX Power Supply initial
state
Off Random
Q: What is the difference of Linear Regulator and Switching
Regulator?
A: Switching regulator turns on/off Power FET with very high frequency and
uses L/C charge and discharge circuit to do voltage drop. The efficient is
better but voltage ripple and EMI noise is higher. The reason for mainboard
designer to consider switching regulator, is simply because they are worry
about linear regulator can not fully support the coming new CPU. Actually,
this depends on the design and layout quality of mainboard manufacturer.
According to AOpen RD's testing, Intel PP/MT-233, AMD K6-166/200/233
are all fine on AP5T to run winstone97. (The CPU is at 53 degree C, heatsink
is at 60 degree C and regulator IC is at 79 degree C). But for future CPU
(perhaps CPU of 1998), AOpen will still consider to phase-in switching
regulator on new version mainboard.
Q: What is the performance improvement of AMD K6?
A: Following is the compare table of the new generation CPU.
DRAM : 64MB EDO
HDD : Quantum Fireball 1280AT
VGA : Matrox Millennium VGA, 4MB, 1024x768 24bit, 85Hz.