Help! Random Power Offs:'(

[Weenaboy]

whenever i play a graphics intensive game, by computer just suddenly powers off after around 20 minutes. i have to unplug the power supply for 20 seconds before my computer will turn on. this has been happening ever since i got my new 9800pro. ive got a 400watt generic, and my system specs are below:

AthlonXP 2800+ @ 2390Mhz (1.81V)
Radeon 9800Pro @ 442/760
512MB DDR400 @ 478 (0.2Volts above stock)
120GB HDD
HP 300N DVD Writer
LiteOn CD-RW/DVD Combo Drive
Antec P160 Case

ive also got my mouse, keyboard, joystick and mousepad getting power from my computer.

after i returned my ram and cpu to stock frequencies and voltages, everything worked fine. but im pretty sure a 400Watt PSU should handle the voltages i set fine. do i have a faulty PSU? should i return it and get a replacement? its still under warranty, thanks for your help.

 

[legcramp]

hint the word "generic" which means ur 400w ps is like 300w....... get an antec... like a 450w one.. or buy a more expensive one like ocz powerstream

 

[BillR]

Yup, sure sounds like you are out of power. Get yourself a brand name “big” power supply, you won’t be sorry. See the stickies at the top of the forum for some good choices. I like the big Antec products, but that’s just me, PC Power and cooling is top of the line and there are many in that list that will work just fine for your needs


Luck

 

[Ice Czar]

as the power supply heats up, its capacity drops
till eventually some combination of component draw exceeds the capacity the supply now has and crash

read > http://hardforum.com/showthread.php?t=839905&highlight=shmower
some background regarding the veracity of generic ratings


and basic instructions on determinung the draw of your components
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Do the math here: http://www.jscustompcs.com/power_supply/
There's a good chance you will need a bigger PSU than the 470..

And once again. Let's not forget that these calculators are absolute worst case.

well as far as calculators goes, that one sucks (sorry)
its very important to actually determine the amps per rail
and not all calculators are automatically the worse case senerio
I use > takaman's Power Supply Calaculator v2
which does have the option to set a utilization percentage, and to manually enter amp values for a given component
which is very handy if you have real world test values like
Power Consumption of Contemporary Graphics Accelerators: ATi
Power Consumption of Contemporary Graphics Accelerators: Nvidia
(all the better because they break out the draw between the AGP and the auxillary connector, which on an ATX12V v2.0 is on different +12V rails)
and various databases like Processor Electrical Specifications
(if the board has a +12V auxillary you add to the +12V otherwise it goes on the +5V rail,
and you convert the watts to amps for the appropriate rail, AMPS = Watts / Voltage)
or the actual spec sheets on the components (like say from Seagate)

that way Im able to run multiple calculations
first I do a "full" calculation, of all the additive maximums of the components
then for an ATX12V v2.0 supply or an EPS12V supply I repeat that for the +12V1, +12V2 and additionaly for EPS12V +12V3\+12V4 rails

then I run a "realworld" worse case senerio,
Its just as likely Im helping someone calculate a NAS as a lean gaming rig
so a "spinup" calculation is the first criteria
all the fans and HDDs\RAID arrays at 100% value and a 25% value for the CPU\GPU, often that will tell me if a more powerful supply is needed simply to boot or if the NAS\SAN need to employ a controller with a delayed spinup option
(common on SCSI controllers, and found on quite a few ATA)
once the fans and HDDs are spinning they will drop to 1\4 of their full rating, so I recalculate with that value as a static load, and throw in a 100% CPU\GPU and single optical (full spinup draw) for a worse case senerio realworld


Interpreting the veracity of a manufacturer is the tricky part
since we dont get to actually see the engineering test specs
which will typically say sometghing like
rated for full power at 25C decreasing linearly to no power at 70C
and your operating temperature being around 40C

generally I start with deducting a third off the rated amps for temperature
and then start to match to the baselines, factor in thermal considerations (PSU placement, type of thermal solution for the rig,) and special factors like overclocking or usage patterns (NAS\Server\Workstation\word processor ),

when I actually make recommendations however I typical build in a healthier safety value than the "real world" worse case senerio unless someone has specifically stated they are running a UPS
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ffor ATX12V v2.0
+12V1 will be CPU, mobo, PCI Cards, fans attached to the mobo and the AGP slot the 24 pin main power connector and Aux +12V mobo connector

+12V2 will be all other connectors including the Aux to the Video Card, drives, fans, lights, pumps ect
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EPS12V supplies are generally for Dual CPU Servers and Workstations, and break out like this

EPS12V 6.1.1 12V Power Rail Configuration

There are two types of 12V rail configurations for systems: 'Common plane' and "Split plane' processor power delivery. The 'commob plane' system has both processors powered from a single 12V rail (+12V1) from the power supply. The 'split plane' system has both processors powered by seperate 12V rails (+12V1 and +12V2) one dedicated to each processor. The system in both cases, has an additional 12V rail to power the rest of the baseboard +12V loads and dc/dc converters. +12V1, +12V2 and +12V3 should not be connected together on the baseboard to ensure that 240VA protection circuits in the power supply operate properly

Table 6: 12V Rail Summary
........................................................................................................................................................................................
Common Plane System........................................................Split Plane System
+12V1........Processors.........................................................+12V1........Processor 1
+12V2........Baseboard components other than processors.......+12V2........Processor 2
+12V3........Drives and peripherals..........................................+12V3........Baseboards and components other than processors
...........................................................................................+12V4........Drives and peripherals

and will have an 8 pin Auxillary +12V mobo connector (2x4)

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examples
http://hardforum.com/showthread.php?t=839454
http://hardforum.com/showthread.php?t=840676
http://hardforum.com/showthread.php?t=840471
http://hardforum.com/showthread.php?t=839756
http://hardforum.com/showthread.php?t=837432
http://hardforum.com/showthread.php?t=837461
http://hardforum.com/showthread.php?t=836393
http://hardforum.com/showthread.php?t=835752