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Bought overclocked computer on eBay, but it's unstable.

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September 30, 2009 5:12:29 PM

[This has been SOLVED Thank you]

Hello all,

I bought the following computer from eBay [Link removed now: But system specs are still listed below]

As you can see, it is advertised as "stable" at 3.1Ghz, however when I got it home it crashed during the first 3 minutes of a game. I tried many different games and it was always crashing within seconds or minutes of gaming. Far from stable! I suspected the system was not stable because of the overclock. I went into the BIOS and saw an option to save the current settings, so I saved the settings as they were so that I could load them again later if need be, and then I chose the option to reset to default safe settings.

Since then, under the stock settings (no overclock at all), the computer is fine playing intensive games for hours, and passed some of the stuff like Memtest that I made it do, so that's how I know the overclocking was to blame for the instability.

The stock system spec is:

Intel Q9400 @ 2.66Ghz, 1333Mhz FSB
8Gb (4 x 2Gb) Corsair PC2-6400 800Mhz Ram
Arctic Cooling Freezer Extreme CPU Cooler
MSI-P7N-SLI-FI Motherboard ("Supports up to 1333Mhz FSB")
2x Zotac GTX 260's in SLI
700W OCZ Modxstream Pro PSU
Three hard drives
Antec 900 Case, with loads and loads of fans...

I reset the BIOS to defaults and then had a go at overclocking it myself, by simply setting the FSB from 1333 to 1400 to go from 2.66Ghz to 2.8Ghz, and even that small increase wasn't stable during gaming.

I have tried for hours today, including by experimenting with upping the voltages, to try and get the system stable at even 2.8Ghz, but it's not having it. The RAM is unlinked and running at its stock 800Mhz although I did try underclocking the RAM to run 1:1 with the FSB, e.g. if FSB was 1400 then I set the RAM to 700Mhz. It had no effect.

Can anyone see any reason why this system won't accept a stable overclock, not even a little? The temps are all fine.

Ps) I get the feeling this seller had the same problem. I believe he built this machine as a gaming rig for overclocking hence the massive heatsink etc, realised it won't overclock so flogged it. It can't have been stable for 3 months as the receipts that came with it show he bought most of the components only 2 weeks ago.
a b K Overclocking
September 30, 2009 5:34:12 PM

Only thing you can do is try to contact the seller or give a negative feedback. This is one reason why you should not sell overclocked systems and should not buy "claimed" stable overclocked systems.

I'm not sure about the conversion rate, but I hope the system parts are worth the 600 pounds.
a b K Overclocking
September 30, 2009 5:39:04 PM

Send it back.

Wait! You can't?

Lesson learned.
Related resources
a b K Overclocking
September 30, 2009 5:47:54 PM

Todays conversion on £600.00 is approximately $960.00USD
September 30, 2009 6:30:20 PM

Don't be so fast to bash the seller...a lot of things can happen during shipping. Contact the seller and see if they are willing to pay for a diagnosis at your local repair tech. There is NO reason that system shouldn't overclock a lot higher than 3.1 even with stock cooling. My best guess is you have some poor memory that is not working correctly. You could try using it one dimm at a time to see if there is a bad module.
If everything is new and under warranty it should cost you nothing to fix, once you find out where the problem is.
a b K Overclocking
September 30, 2009 6:45:05 PM

i hate buying screwed up stuff :(  i'd rather buy it and screw it up myself :D 
October 1, 2009 3:13:59 PM

Twoboxer... What makes you assume I can't take it back? I picked it up by car from the sellers house, so I could just as easily take it back if I can't manage to fix it. I have that option. You win the epic fail award for the most useless post I've seen this week.

Thanks to everyone else though! I did remove the RAM belial but this did not help. I also removed a GTX 260 and that didn't help either (thought it could possibly be the system using too much power, but nope).

If I knew what to replace, I'd just go ahead and replace it. I think I've narrowed it down to either the motherboard or the processor - not a lot else it can be is there?

What would you guys do if you were me? I'm not really interested in taking it back because its 2 hours away and to be fair I think I got a good enough deal even if it won't overclock, I got a computer desk, 17" tft, 5 games, wireless keyboard & mouse, new spare 160Gb HD and loads and loads of other stuff too, I'm not too disappointed and it plays Crysis great, if I can get it to overclock its a bonus.
a b å Intel
a c 197 K Overclocking
October 1, 2009 3:17:02 PM

Start from the stock settings, and OC the thing yourself.

Study the 2 stickies:
HOWTO: Overclock C2Q (Quads) and C2D (Duals) - Guide v1.6.1
http://www.tomshardware.com/forum/240001-29-howto-overc...

Core 2 Quad and Duo Temperature Guide
http://www.tomshardware.com/forum/221745-29-core-quad-t...

With the Q9400 internal multiplier of X 8, you should be able to reach 3.2 GHz.

Anything higher will depend on case and CPU cooling.
----------
Overclocking since 1978 - Z80 (TRS-80) from 1.77 MHz to 2.01 MHz
October 1, 2009 4:02:10 PM

Thanks jsc
I shall give them a read.
I'm already having a go at overclocking myself, 10Mhz FSB increments at a time, but it's not liking it!

Case is Antec 900 with loads of fans, CPU cooler's a good one and temps are nice and low under Prime95 stress test, it should be a good system to overclock but it isn't :lol: 
a b K Overclocking
October 1, 2009 8:24:32 PM

Elaborate..... What exactly are the temps?

What are the voltages?

It should be able to take such a small overclock with just stock voltages. But try to raise them a little bit.
a b K Overclocking
October 1, 2009 8:51:07 PM

I was going to post 'what are the voltages' but overshocked bet me to it.
Even if the CPU isn't a good overclocker, it will be with a little voltage. (assuming RAM and motherboard aren't poopy).

I'd try and make the most of it before you try returning it, often it's not worth the bull you have to deal with when it comes to auction traders. Do it if you need to though, getting screwed sucks.
October 1, 2009 10:59:49 PM

Under hours of stress testing (Prime95 and OCCT) at 1390Mhz/2780Mhz (the highest stable OC I can reach!), the temperature on the hottest core has never exceeded 41oC. The max temps reached according to CPUID Hardware Monitor are 40, 31,41, 37, on cores 0 1 2 and 3 respectively.

In the BIOS I have upped the VTT one notch to "1.225VTT and chosen the highest "safe" setting for the CPU voltage which is "0.1875v". The next highest increment is "0.2000" but that appears in red so I am a bit reluctant to choose it! The NB/SB/Memory remain unchanged from default. These changes I have made to the BIOS have resulted in the following:



That screenshot was taken DURING the torture test if that makes any difference!
October 1, 2009 11:15:56 PM

You gonna need more vcore chuck.
a b K Overclocking
October 2, 2009 12:27:18 AM

+1 for more vCore. Keep it under 1.45v/75C and you'll be fine.
a b K Overclocking
October 2, 2009 2:46:33 AM

Yes it does make a difference (screenshot during torture test).
Yes give it more Vcore. Max is 1.26, safe is 1.45 (as above), so you can keep going up as needed another 0.2V in the BIOS, red or not.

Officially the top is 1.375V (you still have another 0.125V to go). But lots of people running 1.4 or 1.45V without issue. The real killer on quads that I've seen is raising VTT too high (above 1.4).
October 2, 2009 7:08:24 AM

not a bad rig for the money.....think it could use a little more PS for 2xgtx260's should be fine at stock speeds but once you overclock all things including the GPU's will need more wattage....take that for what its worth tens years high end gaming PC builder and extreme overclocker.

a b K Overclocking
October 2, 2009 7:52:07 AM

In a momentary flash of ralism, the OP said:

spencerb said:
Ps) I get the feeling this seller had the same problem. I believe he built this machine as a gaming rig for overclocking hence the massive heatsink etc, realised it won't overclock so flogged it. It can't have been stable for 3 months as the receipts that came with it show he bought most of the components only 2 weeks ago.


But then returned to normal by saying:

spencerb said:
Twoboxer... What makes you assume I can't take it back? I picked it up by car from the sellers house, so I could just as easily take it back if I can't manage to fix it. I have that option. You win the epic fail award for the most useless post I've seen this week.


It is epic *stupidity* not to bring it back to the seller. You bought something you did not get. You found him lying.

The only reason NOT to bring it back is if you can't.
October 2, 2009 8:24:20 AM

A good lesson isn't cheap. I would try and contact the seller to see if he/she is willing to work with you to resolve the issue in a positive way for you.
October 2, 2009 3:07:02 PM

Twoboxer: I have sent my reply to you via PM as I did not wish to litter this thread with silly argument. :) 

Thank you very much all, more vcore you said it needed so more vcore it will get, I shall be trying that now.

itzamedave: I don't doubt you, I know 700W is on the low side, it could need upgrading, will see how that goes. For the moment I have removed a GTX 260 whilst I am trying to overclock the CPU, just to make sure lack of power can't be an issue.
a b K Overclocking
October 2, 2009 8:35:44 PM

^WTF? 700W is NOT on the low side. It's more than enough for a 260.
a b å Intel
a c 131 K Overclocking
October 2, 2009 8:45:49 PM

Quote:
Bought overclocked computer on eBay, but it's unstable.


Yeah, I have same problem w/ my wife and they won't take her back either :) 
October 2, 2009 11:43:07 PM

I am pleased!!!
It is stable at 1560 FSB (3.12Ghz!)
To get this I had to put the CPU Voltage all the way up to the highest possible setting the BIOS will allow (0.3000V), with that cpuZ shows the core voltage at 1.384 (not under load). That's ok isn't it?

The other settings were FSB VTT 1.3000, NB V 1.32, SB V 1.56

I tried for a few hours to get it stable above 3.12Ghz but if that is possible then I think I'd need a VTT higher than 1.4 , because I tried it with all values upto and including 1.4 and it wouldn't pass Prime95, I also tried many combinations of upping the north, south or both bridges to get it stable but it wouldn't have it, didn't want to push it any further by being silly with the voltages!

Thank you for all your help

Ps Shadow, You said "for a 260" but it does have 2 of them, and have 4 hard drives soon, but I hope you are right and the PSU is not on the low side because I'd rather not have to upgrade it :) 
October 3, 2009 9:25:28 AM

Shadow703793 said:
^WTF? 700W is NOT on the low side. It's more than enough for a 260.


On the top of the thread he states he has two GTX 260s. I think he forgot to state what he actually meant. For SLI GTX 260s, obviously 700W would be the minimum. For 1, 700W is more than plenty.
October 3, 2009 9:47:23 AM

I run a higher end 750w bronze plus PS with heat pipe cooling and 2x 120mm fans and with 1 gtx 260 it does fine but when I had 2x9800GTs super overclocked and CPU at 4.66ghz it would barely manage it not to mention all the heat and look at my cooling its pretty good....
October 3, 2009 9:52:36 AM

just remember the I7 alone @ stock speeds or down clocked uses an average of 45w idle and once over clocked its using 150+watts and thats why it gets so hot and requires alot more PS if you are going to overclock same goes for your GPU's overclock=power usage! so start with more PS then you need if you are gonna overclock later.
a b K Overclocking
October 3, 2009 1:42:26 PM

itzamedave said:
just remember the I7 alone @ stock speeds or down clocked uses an average of 45w idle and once over clocked its using 150+watts and thats why it gets so hot and requires alot more PS if you are going to overclock same goes for your GPU's overclock=power usage! so start with more PS then you need if you are gonna overclock later.

What does th i7 have to do with anything?
a b K Overclocking
October 3, 2009 8:43:12 PM

Here's an example review citing a C2D X6800 using 302W at 100% CPU with a single WD raptor. Adding 2x260 at nVidia max spec adds 2x182 = 364W for a total of 666W.

http://www.guru3d.com/article/geforce-gtx-260-review/4

While there's usually headroom in a vid card manufacturer's spec, that total gets a little too close to 700W to say any 700W psu will easily handle it. Most probably will, most of the time. Maybe every time.

If this were a new system build I wouldn't go with a 700W psu. But in an existing build I wouldn't replace a 700W psu immediately either.
October 4, 2009 12:40:45 AM

Don't forget all those Power Consumptions are tested at the outlet. You then have to factor in PSU efficiency.

For Example: You take Twoboxers estimate on 666watts pulled for gtx260sli. Let's assume the machine is running an a decent PSU with 80% efficiency across the board and is capable of producing 700watts rms. If it's pulling ~666w it's then producing ~532.8w, the computers actual power consumption. That leaves the PSU with a theoretical headroom of ~167.2w

Keep in mind the way quality PSUs are rated. They're rated at how much they can produce, not how much they pull.

In other words the current 700w PSU will do just fine with the OPs system.
a b K Overclocking
October 4, 2009 4:43:22 AM

Good point, Lucuis. And I may have fallen into that trap. That review did not describe how it measured power consumption, other than this enigmatic statement:

"We have a device constantly monitoring the power draw from the PC."

In any case, if power draw is measured at the wall we can safely reduce the 302W to 270W. Then add back the 364W manufacturer's spec for the 2x260 because I *hope* that isn't "measured from the wall".

Anyhow, 634W does mean a 700W psu with the right 12V capacity should work OK.
October 18, 2009 7:46:49 PM

so the system is stable at 3.12v now? do soem torture tests and get back to us! im glad your didnt get totally screwed
!