[about misbehavior in odd circumstances after RAM install]

There are some complications that can be dismissed, like

(a) the standby power is a small +5V supply, and runs some watchdog
circuitry, and perhaps the system clocks. PC3200 RAM uses 2.5V. It
is completely irrelevant to memory install whether 'standby' is off or
not.
Off is recommended, just in case wires get crossed during install.

(b) SDRAM is not a heavy consumer of power, it is NEVER necessary
to upgrade the power supply when adding SDRAM.

(c) startup with a 'new' RAM configuration always does different
things
from normal, because there are new memory-map tables to be
constructed.
Even if you set the BIOS to skip long memory test, a long memory test
WILL occur.

(d) immediate startup on power-connect is a normal behavior for lots
of server-class machines. If it surprises you, check the BIOS
settings and
the battery.

There are two explanations to the odd occurrence: the memory-table
build
step could be not fully supporting the new configuration (look for
BIOS
flash upgrades and/or try another memory-slot for the big modules), or
maybe the power parts on the logic board are full of dying capacitors
and sometimes the good RAM fails a memory test due to noisy power.