# PC Shuts down suddenly without warning



## rktboy (Feb 19, 2009)

I've been struggling with this for months and am at my wit's end. Any help anyone could offer would be greatly appreciated!

Basically, without warning, my computer, for no apparent reason, shuts itself off. No shut down. It simply shuts off, as though the power had been disconnected. (It might be worth noting that on starting it back up again, chkdsk doesn't run.)

At first, I thought it was a random occurence and likely a hardware problem; possibly the Power Supply. However, my MoBo is set to power up the computer after losing power and, after one of these unexpected power downs, the computer doesn't start back up until I hit the power button.

I've also started to notice a link to downloading. Namely, if there's multiple downloads going on, it seems to trigger the problem. It shuts down almost every night, which is when I've got utorrent scheduled to run, and I've been able to trigger the problem reliably by initiating multiple downloads of podcasts in iTunes. It also seems to happen sometimes when web pages are taking too long to load.

It's probably important to note that the computer functions perfectly otherwise. I can tax the system with the latest games or a heavy set of video transcodes without incident, so I'd have a hard time believing it would be a heat problem. 

Based on suggestions from others, I have tried replacing the RAM and Network Card, but neither has had any impact on the problem.

Any help anyone can offer would be greatly appreciated.


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## grimx133 (Jan 15, 2008)

When a computer powers off as if the plug has been yanked from the wall, and doesn't give a stop message (bsod), it's mostly one of two things. Heat or power.
Go into your bios and check in the power section for hardware monitoring or pc health or something worded similar.
Let us know the temperatures and the actual voltages for the +3.3, +5, and +12 volts. The bios is the most accurate, windows programs have a lot of variation and outright error, need the values from the bios.


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## rktboy (Feb 19, 2009)

Ok, just took a peek...

System Temperature is 41 degrees C
CPU Temp is 34 degrees C

Voltage on +3.3 is 3.28V
Voltage on +12 is 12.112V

I didn't see an entry for +5


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## grimx133 (Jan 15, 2008)

What are your complete specs?

-motherboard
-videocard
-cpu
-power supply - take off the side cover and look at the label for the manufacturer and
model number. Also the output (in amps) from all the rails +3.3,+5,+12
-how many drives, both hdd and cd/dvd
-basically everything. 

You can get most of this with pc wizard. Either attach a txt report or type the hardware in. If you attach a report, make sure to edit out the nonhardware stuff, like passwords. We don't want those.
The power info is not obtainable without physically looking at the label, unless you know what it is already. It is very important, so don't skip that.


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## rktboy (Feb 19, 2009)

OS: Microsoft Windows XP PRO
Hard Disk: Western Digital 750G SATAII 7200 rpm HDD(16Mb Cache)
Floppy: Internal Card Reader with Slim Floppy Drive Black
Optical Drive: Samsung 20xDVD -/+R/RW Dual Layer OEM Black SATA
PSU: Corsair VX-450 ATX 450W Power Supply 120mm fan
RAM: 2 x DDR2 2048MB(2x1G)PC6400 800Mhz Hyper Memory with blue heatspread Kingston
Sound Card: Creative Sound Blaster X-Fi Xtreme Audio Card PCI Express
Video Card: Gigabyte GF8800GTS PCI-E 512MB GDDR3
CPU: Intel ATX E8200 CORE 2 DUO /2.66GHz/6MB/1333FSB/LGA775
Motherboard: Gigabyte EP35-DS3 P35 1333Mhz
CPU Cooler: Thermaltake Blue Orb 2
Case: NZXT Lexa Mid-Tower Case

Specs on the PSU are:
DC Output // Maximum Output Current // Maximum Combined
+3.3V // 20A // 140W
+5V // 20A // 140W
+12V // 33A // 396W
-12V // 0.8A // 9.6W
+5VSB // 3A // 12.5W

(If it matters at all, I also have an External 750GB Hard Disk in a Vantec Enclosure)


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## rktboy (Feb 19, 2009)

Here's PC Wizard's report if it makes things easier...


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## Tumbleweed36 (May 14, 2005)

A 450 watt power supply is normally not powerful enough to run an 8800gts. Try a minimum of a 550 Corsair in there, and if it were mine, I would put a 650 watt in there.


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## rktboy (Feb 19, 2009)

Tumbleweed36 said:


> A 450 watt power supply is normally not powerful enough to run an 8800gts. Try a minimum of a 550 Corsair in there, and if it were mine, I would put a 650 watt in there.


But if the capacity of the CPU were the problem, the system would fail under load, right? And it doesn't. I can run current games with settings maxed and really punish the system and it remains solid.

The power losses occur when the video card isn't even being used!


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## rktboy (Feb 19, 2009)

P.S.- Thanks for all the help you guys are offering!


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## grimx133 (Jan 15, 2008)

It is odd that it doesn't cut off in games, but the system is a lot more than just a video card, even though it's the single largest power sucker. 
Ran it through a psu calculator with 30% capacitor aging and came up with 377 watts. Factor in efficiency and some overhead and you're up there. Like Tumbleweed36, I wouldn't run that card on anything less than 650. Forgot to ask, do you overclock at all, cpu and/or graphics? That really burns power. 
And, do you know anyone with a decent larger psu that you can borrow and see if it shuts down with that? Preferrable something with 40-50+ amps on the +12.


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## rktboy (Feb 19, 2009)

No, nothing overclocked. Everything is running at stock settings.

I'll check to see if I can get my hands on an alternate PSU


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## grimx133 (Jan 15, 2008)

Be nice to be able to rule it in or out eh. 

Thing of it is, if it was ram or drivers or anything like that, you'd get a blue screen, and your temps aren't out of line. 

One weird thing in the report, shows your ram with a PC2-6400 part number, but then show the ram operating at PC2-5300.
Copying in something from the ram section.

>> Memory Information
Type : DDR2-SDRAM PC2-5300
Frequency : 333.3 MHz
DRAM/FSB Ratio : 1/1
Supported Channels : Dual (128-bit)
Activated Channels : Dual
ECC Diagnostic : No
CAS Latency (tCL) : 5 clocks
RAS to CAS (tRCD) : 5 clocks
RAS Precharge (tRP) : 5 clocks
Cycle Time (tRAS) : 15 clocks
Command Rate : 1 T
Shared Memory (video) : Yes 

It shows 1T for the command rate there, everywhere else it shows 2T. The 2T is normal for ddr2 ram, what does it say in the bios?
Shot in the dark, but what the heck.

I have to run, be on again tonight.


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## siuengr (Mar 12, 2009)

I just put together a brand new machine and was having a similar problem. I was using an ASUS M3A78 MB and 2x2GB corsair ram. The OS loaded fine, but then I would get random crashes.

From the error code I got a clue that it might be the ram, so I made a memtest CD. Sure enough it crashed as soon as the memtest started. I took out one stick of ram and memtest passed with flying colors. Swapped sticks and it passed again. It only fails when both sticks are installed.

I left one stick in and it has been running fine since then, something you might want to try. I am trying to contact ASUS support to see what the problem is, but I have heard they haven't been overly helpful.


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## Sparky09 (Sep 17, 2008)

It could still be heat if you ask me. Strange if it doesnt crash on games mind you but still a possibility. Make sure if it does it again you check how hot that heatsink is. Checking the temps in bios may not give you accurate readings (unless you check them as soon as the system shuts off) because the cpu will heat up more when you run it heavier (a.k.a downloading lots at once). Other than that my first guess woulda been power supply too. One more suggestion... unlikely to be software by the sounds of it but just in case it happens to be something triggering the system to crash like that in the software... right after you reboot it after the crash check the event viewer--start-run-eventvwr.msc and see if there's any indication under "system" at the time of the crash that shows an error.


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## rktboy (Feb 19, 2009)

siuengr said:


> I made a memtest CD.


Yeah, I was initally worried about RAM too. I ran memtest86 overnight without a hitch. I even went so far as to completely replace the RAM, but the problems persisted.

...On the plus side, I now have 4GB instead of the original 2! :normal:



Sparky09 said:


> It could still be heat if you ask me.


Heat was my first thought, but I've monitored it closely and all the components are nice and frosty right after one of the power-offs.



Sparky09 said:


> ...check the event viewer


The only recurring warning around the times of the power-offs in the event viewer is something about multiple connection attempts or something, which I'm assuming has to do with the multiple downloads. (I'm at work at the moment but will post the exact message when I get home).


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## rktboy (Feb 19, 2009)

grimx133 said:


> One weird thing in the report, shows your ram with a PC2-6400 part number, but then show the ram operating at PC2-5300.


I'll be able to answer your question when I get home.

In the meantimen, I did a little surfing and found this post, in a review of my RAM on Newegg...



> These modules are advertised as DDR2 PC6400 modules, but if check the Kingston Data sheet for these modules you will find, "The SPD is programmed to JEDEC standard latency 667Mhz timing of 5-5-5-15 at 1.8V." Therefore, if you are not apt to overclocking or your motherboard's BIOS does not allow for full control of timing and clock settings you could literally be "left holding the bag" with modules rated at DDR2 800 (PC2-6400) running at DDR-667 (PC-5300).


I should note that my Mobo DOES allow for control of memory timing, but that's all the way into "over my head" territory, so I've never messed with it.

Is any of this related to my problem? The bulk of reviews on Newegg for that RAM are pretty positive.


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## grimx133 (Jan 15, 2008)

That sounds like it runs ok, but slower. I'm wondering more about the 1T command rate. If it does show that, try changing to 2T. Problem is, where is it. Was thinking you had an asus board, knew where to go there. So I scrolled up and saw it was Gigabyte, and I have an EP35-ds3l manual here, but couldn't see the setting. Will check if ctrl+f1 shows it, but that I can't do until I get home tomorrow and have a chance to go into the bios of that board.


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## rktboy (Feb 19, 2009)

I'll have a crack at it when I get home.

Whereabouts are you in Canada, Grim?

I'm a displaced canuck who migrated to Australia last year to marry my wife.

You'd be surprised how little time it takes to miss snow =)


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## rktboy (Feb 19, 2009)

Ok, I think I may have a source for a power suplpy to try out but I won't be able to get my hands on it till some time tomorrow.

It's a Corsair VX-550, one model up the line from my existing PSU. It's capable of handling 41A on the +12V rail so it's a bit of a step up.

I'll report my results.

Can I ask a question though? I have my MoBo Bios configured to restart the computer after power loss, which it does after a proper blackout (or just unplugging it...which I don't ever do, for the record!). 

If the problem does turn out to be my PSU, why wouldn't the computer restart after one of these power off episodes?


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## grimx133 (Jan 15, 2008)

If it's the psu and it shuts itself off, it's not going to turn itself back on, with going back into the same conditions it would most likely create a reboot loop. A power failure is an inadvertant shutdown and not usually any problem. I always set the bios to stay off, would rather wait and make sure it's going to stay on. Those times when the power keeps kicking in and out aren't good for the computer if it's trying to start up and getting cut off over and over.

You can have the snow, northern ont here, and this year there's been more than usual. It does seem that the driving was worse last year, a matter of timing and when I had to be driving, I guess. And it was -19 with a windchill of -26 yesterday morning, no way you can miss that.


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## grimx133 (Jan 15, 2008)

Well, I've scoured the gigabyte bios here and can't find any way to set the command rate. Check with cpu-z, it's a standalone prog, doesn't install, just runs from wherever it is. The memory tab should show the command rate. Probably a red herring in the report, but worth a look.


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## grimx133 (Jan 15, 2008)

Something just caught my eye a few posts back, that you're running with 4 sticks of ram. Check to see what your ram is rated for and see if you have any room to increase the voltage for it. Voltages that run 2 sticks stable often won't run 4 as good. Depends on the ram though, don't exceed the manufacturer's limit.


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## rktboy (Feb 19, 2009)

grimx133 said:


> Well, I've scoured the gigabyte bios here and can't find any way to set the command rate. Check with cpu-z...


Yeah, I couldn't find it either. cpu-z lists the command rate at 2T.



grimx133 said:


> ...that you're running with 4 sticks of ram.


I'll look into that, though I should mention that I was having the same power-off problem before adding the second pair.


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## grimx133 (Jan 15, 2008)

Was looking at a review from Feb/07 on this ram. 


> Kingston's official specs for these modules are 4-4-4-12 at 800 MHz, which requires a voltage of 2.0v. When you first boot a system up with this ram installed, the SPD timings will be 5-5-5-15 667 MHz @ 1.8v. This will ensure that they comply with JEDEC standards, which prevents issues with boards not booting up properly due to the higher voltage requirement, etc.
> 
> All HyperX memory modules come with a Lifetime Warranty. These particular modules are warranted up to 2.1v, so you have a little bit of headroom, but not as much as with OCZ.


http://www.hardcoreware.net/reviews/review-353-1.htm


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## rktboy (Feb 19, 2009)

I just had an awful thought.

If I really am maxing things out, as far as the output of my PSU is concerned, could it be an external USB device that's pushing my system over the edge?

Namely, I have a Logitech G7 mouse that comes with it's own battery charger. Could the current draw of it be just enough to tip it over the edge?

That's the only one I can think of that would be drawing any measure of current.


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## rktboy (Feb 19, 2009)

rktboy said:


> ...could it be an external USB device that's pushing my system over the edge?


Nope. Just tried unplugging it and computer still powered off.


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## rktboy (Feb 19, 2009)

Alright, just got finished testing with the VX-550 Power Supply and no joy. Exact same results.

:sigh:


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## grimx133 (Jan 15, 2008)

Did you check to see what your ram voltage is? Looks like it defaults to 1.8v. when that particular ram is installed. The ram is rated for 2.1, so try increasing it, if it's still at 1.8.


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## rktboy (Feb 19, 2009)

grimx133 said:


> ...The ram is rated for 2.1, so try increasing it, if it's still at 1.8.


The DDR2 voltage was reading 1.904V

I've set the DDR2 Overvoltage Control (In the "MB Intelligent Tweaker" menu in my bios) to +.3V and it's now reading at 2.112v in the "PC Health Monitor" menu.

Is that the right procedure?


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## rktboy (Feb 19, 2009)

-----


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## grimx133 (Jan 15, 2008)

Sounds like it got the voltage up there. I was looking through the manual a few minutes ago for that, too bad you can't just set the voltage to whatever. Probably why I do all my overclocking and stuff on my asus board instead of my gigabyte eh.


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## rktboy (Feb 19, 2009)

Still getting the same problem with the voltage increased. 

Is it possible I have a faulty component somewhere? The ends of all my warranties are fast approaching so if something does need to be replaced, it'd need to be soon.


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## grimx133 (Jan 15, 2008)

Was thinking the same thing, have you tried running it with minimum components? Disconnect on drive at a time and test to see if it helps. btw, your hard drives are awfully full there, you're in serious need of some space.

Another thought, have you tried with just one stick of ram?


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## rktboy (Feb 19, 2009)

grimx133 said:


> you tried running it with minimum components?


No, but I suppose that's the next step. Process of elimination, right? 



grimx133 said:


> btw, your hard drives are awfully full there, you're in serious need of some space.


Yeah, I'm due for a serious backup session. I'm just procrastinating.



grimx133 said:


> Another thought, have you tried with just one stick of ram?


No, but I'll make that the first thing I try.


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## grimx133 (Jan 15, 2008)

Try with just your OS drive. Unplug whatever you have for cd/dvd, and the external. Shouldn't really run an external all the time anyway. Lots of problems with them, and there seems to be link to how much they are ran. Seems they don't deal with heat well. I only plug mine in when I need to put something on, or take something off. 
Pci cards etc., if any, that you don't need should come out too. Anything usb, unless it's kb and mouse. 

With the ram, you may need to try all 4 sticks separately.


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## rktboy (Feb 19, 2009)

I had class last night so I haven't had a chance to check this yet. I will tonight for sure.

Quick question: I've upped the voltage of the RAM to 2V but how do I go about upping the clock speed to the rated speed? Is that in the BIOS too?

Grimm, and everyone else, thank you for all the help you've been. Even if we don't get to the bottom of the problem (though I haven't given up hope just yet), I've learned a lot!


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## grimx133 (Jan 15, 2008)

Your cpu isn't running at the proper clock speed? Or you just want to OC it?

Anyway, give the linked thread a read, it'll show you what settings to adjust. Linderman has a template for your board at the end, but read the whole thing. Lotta good info in there that will apply to you. Might help with the prob too. 
http://www.techsupportforum.com/f273/ram-overclock-question-348153.html


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## rktboy (Feb 19, 2009)

grimx133 said:


> Your cpu isn't running at the proper clock speed? Or you just want to OC it?


No, I meant my RAM. It's rated for PC6400 But was listed at PC5300.

Or is that not an issue now that I've corrected the voltage?


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## grimx133 (Jan 15, 2008)

What did cpu-z say for your ram? It will show 400 if it's running at 800Mhz and show 333 if running at 667. If it does show an actual speed of PC2-5300 ram, then you can OC the ram to get it up to the rated speed. You can do that with the dividers and do the ram only, or speed up the cpu at the same time.


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## rktboy (Feb 19, 2009)

grimx133 said:


> <it will> show 333 if running at 667.


Yes, it's showing 333.3 MHz

Should it be 400?


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## grimx133 (Jan 15, 2008)

The report showed two values, the 800Mhz PC2-6400 and the 667Mhz PC2-5300. It should be running on whichever the ram is rated at, but that wasn't clear in the report. Double check your documentation, or the website where you purchased it, and make sure which one it is. Or you can look at the label on the sticks. If the two kits you are using are different speeds, the faster ram will clock down to the slower rams speed. 
While your at it, can you get the make and exact model numbers for the two ram kits, I want to check with the ram manufacturers for compatability.


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## rktboy (Feb 19, 2009)

I'm sorry I haven't got back to you sooner. Between work and school, I've been swamped.

The exact model number on the RAM is KHX6400D2LLK2/2GN and it's definitely rated for PC2-6400.

All 4 sticks of RAM are the same model.

Using a tuning app that came with my Mobo (Easy Tune5 Pro), I've set the clock speed on my RAM to 800 Mhz and it seems to be running smoothly (no effect on my problem though).

I'll be stripping the PC down to the bare minimums tonight and swapping around the RAM sticks. I'll post the results later this evening.


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## rktboy (Feb 19, 2009)

What a night...

I unplugged everything I could get my hands on in my machine. The only components left plugged into my mother board were the CPU, the video card, a sound card and my hard disk. I even went so far as to disconnect the front panel USB header connectors!

I then began to test the sticks of RAM with the following (ultimately disastrous) results.

For lack of a better name, let us refer to each stick as Stick 1, 2, 3 and 4.

I started by removing all but Stick 1. I set up a number of files to download and the computer promptly shut itself off.

Then, I pulled out Stick 1 and replaced it with Stick 2. Began a series of downloads and, to my surprise, no failure.

Next, I pulled Stick 2 and replaced it with Stick 3. Same results. No shut down after 15 minutes of solid downloading. My hopes began to rise that I might have sourced the problem!

Next, on to Stick 4 (after pulling out Stick 3).

Bad times ensue.

My computer boots and enters windows and before I can do anything, I lose power. I pull Stick 4 and put Stick 3 back in. Upon restarting, I am given an error stating "Windows could not start because the following file is missing or corrupt: \Windows\System32\Config\System"

My heart sinks.

2 hours later, I've been able to reinstall windows and, after a few driver glitches, namely getting my keyboard and mouse working again, I'm back in business. I've a few other bugs to work out (as one always does after a windows rewrite) but I'm back in business.

There is an upside here, in that I may have found the source of my troubles. I'll leave it downloading overnight to be sure, but I have set up multiple downloads and things are stable so far.

I'll keep you posted.


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## rktboy (Feb 19, 2009)

rktboy said:


> I'll keep you posted.


Well, no failure as of theis morning. I've left it downloading and will see when I get home today.


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## grimx133 (Jan 15, 2008)

Ram can be such a pain sometimes. Hope it keeps on working without shutdowns.


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## rktboy (Feb 19, 2009)

grimx133 said:


> Ram can be such a pain sometimes.


What has me concerned is this:

These 4 sticks of RAM were purchased in pairs of two. Each pair was purchased at a different time (seperated by almost a year). For the record, from a different vendor as well.

Of the two bad sticks (if they are indeed bad), each comes from a different pair.

Isn't that sort of astronomically unlikely!?

I mean, I could maybe see it with no-name RAM but this is Kingston! 

Anyways, if it does turn out that I've sourced my problem (fingers crossed), that RAM came with a lifetime warranty, so I can get it replaced.


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## grimx133 (Jan 15, 2008)

They like the kits returned intact, one bad stick and they want both back. May have to return one kit, then when you get that back, return the other. Or, return them both at the same time, if you can borrow some working ram somewhere.


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## rktboy (Feb 19, 2009)

grimx133 said:


> They like the kits returned intact, one bad stick and they want both back.


Do you think I could pull a fast one and return both bad sticks as a set?

Thay ARE identical!

:wink:


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## rktboy (Feb 19, 2009)

Alas,

I've come home to a shut down computer.

grrr.


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## grimx133 (Jan 15, 2008)

Run memtest on one stick at a time for 2 hours each. Download the .iso and make a bootable cd. http://www.memtest86.com/download.html


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