Computer shut off....PSU the reason?

[dino26]

Well i consider myself pretty knowledgable about most pc harware related things but I would like some second opinions.
I thought my system was perfectly stable at 3.8ghz (e8400 3.0ghz@3.8ghz)
I ran benchmarks and tests to determine it is stable and everything seemed to pass. I havent had this for too long and i noticed on 3 occasions now that the system ramdomlyu just shut off (all power off instantly) in the middle of a couple games with lots of graphics on screen.
I did not notice this with one video card (hd3870) when i also only had the system at 3.6ghz...when a game crashes and it says the video stopped responding i know it was me overclocking the video cards too muuch..if the it is another crash i think it could be the processor too much oc but wiith all power jsut going off only in the middle of high graphics i am thinking that perhaps i am pushing the ps too much since the more you oc a processor and graphics the more watts it uses. I am using a 600w silverstone strider psu which is on the approced crossfire list. I have all this inside:

(1)e8400@3.8ghz
(2)hd3870 small oc
(2) 74gb raptor 10k rpm
(1) 320gb hdd
(1) 250gb hdd
(4) gb ram
(1) internal burner
(1) external burner
FANS (1)cpu (2) graphics (4) system

 

[mpilchfamily]

Well your PSU is able to offer a max of about 48A on the 12V rails. This should be enough to keep the system running even with it OCed. But then again you could be hitting a temporary spike in the load during the game which tripes the OCP shutting off the PSU. All it takes is for the CPU, HDD and GPU to peak at the same time and just barley exceed that 48A max for a split second. But there is no way to tell for sure. See if you can borrow a larger PSU for someone to help you rule out any other issues the system may have. If not then you may have to pull back on the OC a bit so that your not wasting money on things you might not need. Besides your not going to notice a difference in gaming with the CPU running a couple hundred MHz slower.

 

[Billb2]

Note that the 55 amps (spec) that are on the 4 X 12v rails, totals 660 watts (12v x 55 amps = 660 watts), yet the PSU can only put out 600 watts form all the rails. Total for all the rails is 933.9 watts. 55watts is the current carying capacity of the rail, not how much curent the PSU can actually put into that rail. You can try splitting high current drawing devices to different rails. Checking all the rails (under heavy load) with a digital volt meter would tell you exactly what is going on.

 

[jonnyGURU]

Originally posted by: Billb2
Note that the 55 amps (spec) that are on the 4 X 12v rails, totals 660 watts (12v x 55 amps = 660 watts), yet the PSU can only put out 600 watts form all the rails. Total for all the rails is 933.9 watts.

What? No.

+12V rail capability on that PSU is 504W. Not 660W.

They take that 504W rail and split it into four. They then put 8A, 13A, 16A and 18A limiters on each of those rails. You don't add up the limiters.

OP: Depending on the revision of the PSU you have, the PCIe connectors may or may not be on +12V3. +12V3 is rated at 16A, so that should be enough (with each PCIe connector rated to carry no more than 6.25A each).

Some of the very early ST60F units had a different set up. I can't remember what it was, but it caused problems with SLI/Crossfire.

If you want to test this, just pull one of your cards and do everything with just the one card plugged in. You said you believe it worked before with one card, so just try it again.

If this works, swap the cards to see if it's just a defective card. If it works with either card, but not with both, there could be just something wrong with PSU. Like I said, it should be enough, but that doesn't mean there isn't anything wrong with the PSU or it's not the really old version with it's "known issues" with SLI/Crossfire.

If one card causes the shut down and not the other, then I would suspect one of the cards is bad.

If either card causes the PC to shut down, then I would suspect the motherboard.

 

[Billb2]

Originally posted by: jonnyGURU
What? No.

+12V rail capability on that PSU is 504W. Not 660W.

...You don't add up the limiters.

Sorry, I just took the specs of the first google hit I got for silverstone strider psu , obviousley it was the wrong model.

"You don't add up the limiters"
That was the point I was trying to make.
You did it much more eloquently...as you always do!

 

[dino26]

wow you guys are psu knowledgable. thanks...i have a couple days off comming up so i will try using my volt meter and also try each card seperately and together to see if i can find an issue. I did test the readouts in software and it seemed like all the volt readings were very close to what they should be...I mean close enough to where it didnt look like an issue with any of the rails putting out a dangerously low or high voltage.

 

[jonnyGURU]

Originally posted by: dino26
I did test the readouts in software and it seemed like all the volt readings were very close to what they should be...I mean close enough to where it didnt look like an issue with any of the rails putting out a dangerously low or high voltage.

Right, but there's a few problems with that....

1. Software/BIOS readings are notoriously inaccurate.

2. You can't monitor those voltages while the PC is "under load". Voltages aren't going to be static even in the best PSU's. They tend to dip under load and if the PSU is defective, they'll dip out of spec.

3. If the voltage suddenly dipped out of spec and caused the PC to shut off or reboot, software wouldn't catch is anyways. It would catch the moment just prior to the voltage dipping.

Besides, I don't think it's a problem of the PSU overloading or poor voltage regulation. It's either a bad card, bad motherboard or the two cards are overloading the rail that the PCIe connectors are on causing the PSU to shut down; which means it's shutting down because a set current limit is exceeded... not because a voltage dropped out of spec.

 

[dino26]

I figured out the problem and I feel stupid now!


LOL.....I have not lived in this new house long so I did not realize that the power in the house kind of sucks.....i have almost all 2 prong wall outlets and the one 3 prong in my room is apparently on the same circuit as some other rooms such as one of my housemates. Also i had to use an extension cord to reach it then a surge from the extension......just barely movinng the wires under my desk would cause everythign to turn off in my room and my housemates room too. I got rid of the extension cord and I took one surge and got an adapter and spread out everything i have plugged in and no more problems.....i guess we were just overloading the circuit......well at least i dont have to go buy a $150+ psu or rma a graphics card....thanks for all the advice though I really appreciate it and I think I learned a few new things.

 

[imported_wired247]

Another tip. Vacuum cleaners and blow dryers (got a girlfriend?) can pull a ton of current. don't plug one into the same power strip/circuit/etc as your computer. It could cause your computer to shut down or worse.