Ronald Reitch LMT said:
Hi I have an P5P800 Asus and I just got a Antec EPS12V Truepower 550W
PSU 2.0 version (24 pin).
First under power in bios it list ACPI. Does this refer to my new
Antec 2.0? Do I enable it? What benefits does enabling it to 2.0 table
do?
-------------------------------------------------------------------
CPU.............Intel Pentium 4 LGA775 530 Prescott 3.00GHz
Mobo....ASUS P5P800 BIOS Rev 1005
Chipset.....Intel i865P/PE/G/i848P rev. A2
Southbridge Intel 82801EB (ICH5) rev. 2
System Memory...........2048 MB (DDR SDRAM)
{4-Corsair XMS CMX512-3200LL modules}
Power supplies are not enumerated by a computer. There is
no communication between the PSU and the CPU. The monitor
chip can read the voltages, and that is about all the
intelligence that is available (maybe PSU fan speed, if you
have a fan speed cable).
This is a good page for ACPI info:
http://en.wikipedia.org/wiki/ACPI
You can download an ACPI 2 spec here. They don't have a nice
summary section listing the differences, so it isn't easy to
say what the user visible differences might be, when you
change that BIOS setting. I would say, if your computer sleeps
and hibernates properly, and shuts down properly when asked to
do so, just leave the setting the way it is.
http://www.acpi.info/
The "2.0" in your new power supply, refers to the ATX power
supply spec. The version 2.0 spec changes the power connector
from 20 to 24 pins. It also splits the 12V rail into 12V1 and
12V2. One of those 12V outputs, powers only the processor. The
other 12V output powers disk drives and the rest of the
motherboard, including video cards.
http://www.formfactors.org/devlist.asp?FFID=1&CatID=2
12V was split in two pieces, AFAICT, to limit the power on
an individual output. This allows the power supply to receive
certain "agency approvals". Basically, the purpose of limiting
the power on any transformer output, is to reduce the risk of
fire, if a short develops that cannot be detected as a fault
by the supply.
The down side of splitting the 12V output, into two or more
separate outputs, is there is not sharing of any over-abundance
of power on one output, with the other. Say, for example, that
your processor doesn't use all the power available on its
private supply. That abundance cannot be donated to your
video cards. This is fairly important on an SLI setup, and is
one reason why what would otherwise be decent supplies, do not
seem to work well.
As an example, compare the Turbocool 510 from pcpowerandcooling,
to their newly offered 850 watt supply.
The 510 versions are here. A single 12V rail shared by all loads.
http://pcpowerandcooling.com/products/power_supplies/maxperformance/turbocools/index_hp_atx.htm
+5V @ 40A
+12V @ 34A/38A
-5V @ 0.3A
-12V @ 2A
+3.3V @ 30A
+5VSB @ 3A
power=510W
The 850 version is announced here:
http://pcpowerandcooling.com/about/index_whatnew850.htm
It has four 12V rails, each limited to 17 amps. I think I would
rather have one 34 amp rail, than four 17 amp rails where not
all the power can be profitably used/shared.
Heres an entertaining thread on power supplies that may be of
interest to anyone shopping for a supply.
http://www.xtremesystems.org/forums/showthread.php?t=56231
HTH,
Paul
