Unknown issue causing system shutdown

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After having my desktop packed up for the last year or so I took it out to do some gaming, and immediately found something wrong.

At first it appeared that the system was going into shutdown to protect itself from overheating, but when checking pc temp immediately upon restart in BIOS it appeared that it wasn't the problem. Temps were nearly 10 degrees C below the shutdown limit of my motherboards default BIOS settings (Pheonix Award Bios in a DFI P-35 BloodIron.

I am still thinking it may be overheating, but that being said I noticed signs that video memory may be in the early stages of corruption/going bad. It only happened once but when moving a window the telltale colored lines appeared on-screen. That only happened once and I haven't been able to repeat it.

I ran a prime95 torture test in all three modes and all three resulted in system shutdown without generating a report.

The system only shuts down when under extreme stress (gaming on high settings, or diagnostic torture tests, and the like) which led me to believe it may just be a heat issue, but the temperatures reported by BIOS is anomalous.

The system speaker is talking to me. Usually before shutting down it will emit short very rapid series of beeps. Sometimes it will do this 2 or 3 times before shutting down, and the pc shrieks are spaced a few minutes apart, but I can't find any useful guideline to make sense of this code. I know some of the other codes, but I can't get anything about this one.

System specs:

DFI P-35 BloodIron MB
Intel Core2Duo e6750
6GB DDR2 RAM (Kingston, I have forgotten which series)
Sapphire AMD/ATI Radeon HD 3870 512mb

I haven't made any changes to the system in 4 years except for upgrading the RAM two years ago, and have had no problems until just the last few weeks after unpacking it.

The thought crossed my mind that I need to take a can of compressed air to the inside of the case because dust may have collected making it difficult to cool properly, but the Prime95 test and the temp readout makes it difficult to pinpoint the problem.

[Murf]

If the video card has a fan, then it may not be working and the video card is overheating. Clean out the case, reseat all cards and cables. See if that helps.

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Murf - Thanks for the reply. I also thought that the videocard fan may not be cooilng the card properly. I have ordered a whole new videocard since I have been wanting to upgrade that anyway. Once that is installed I will see what happens with the shutdown problem. I have also ordered a few cans of air duster to give it a good cleaning.

I will reseat all cards and cables and see what happens with that and report back.

On a side note can anyone tell me what the current standard of atx power supplies are? If memory serves I installed a 700w psu when building this system nearly four years ago. When looking online I saw a lot of listings for psu's in about the 5-600 range, which confused me a bit and led me to wonder if that 5-600 is the recommended wattage for a mid-range gaming machine.

Thanks again and kind regards.

[Murf]

Power Supplies should not be purchased just based on wattage. It should be based on amperage.

The power supply is there to convert the high voltage from the wall outlet into the lower voltages required to operate the computer circuitry. If this is not done properly, the irregular power signals that are sent to the components can cause damage and system instability.



There are three primary voltage rails inside of the power supply: +3.3V, +5V and +12V. Each of these supplies power to the various components of the computer system. It is the combined total power output of all these lines that make up the total power output of the power supply. The formula used to do this is:

• Wattage = Voltage * Amperage

The most important voltage rail in a power supply is the +12V rail. This voltage rail supplies power to the most demanding components including the processor, drives, cooling fans and graphics cards. All of these items draw a lot of current and as a result you want to make sure that you purchase a unit that supplies enough power to the +12V rail.

You will also see many new power supplies having multiple 12V rails that will be listed as +12V1, +12V2 and +12V3 depending on if it has two or three rails. When calculating the amps for the +12V line, it is necessary to look at the total amps produces from all of the 12V rails.

Amperage = Wattage / Voltage

With this information about the +12V rails, one can use it against a general power usage based on the system of the system.

Modern day Video cards can draw heavy on the +12v rail, you will see many of them recommending at least 20A + on the +12V or a 400W power supply minimum.

So when choosing a power supply be mindful that those 750W+ may not have as much amperage on the +12v rail as say a 500W. However, generally the greater the wattage the greater the amperage on the +12v rail, but not always the case.

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Very insightful reply. I will check the amperage rating of my current psu.

Thanks and kind regards

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I upgraded my video card and thoroughly cleaned the inside of the computer with a can of compressed air and all problems ceased immediately. I am still not sure if it was indeed shutting down due to overheating, but after I changed the videocard I immediately saw core cpu temps drop by more than 15 degrees C after long rounds of gaming on maxed settings, which leads me to believe that perhaps the cpu and/or RAM was picking up a lot of the slack my old videocard was leaving since it was in fact outdated for playing modern games on high settings, and the new video card with improved cooling technology coupled with it's high specs has taken a lot of the load off the cpu and memory.

Again I'm not sure if that's true, but seeing as the shutdowns have stopped, and core cpu temps reported in bios are so much lower it seems to be a logical conclusion that the upgraded hardware and a good cleaning solved the problem.

Thanks for the advice, and information about psu's, I will keep that information in mind during my next build.

Kind regards and thanks again.