Can a bad processor damage a mobo

[oynaz]

OK, my friends computer died a spectacular death. Both the mobo and PSU were gone, and he decided to do a major upgrade. He has given his P4C 3,0 ghz CPU to me, to replace my own P4C 2,4 Ghz. Only problem is, the CPU might possibly be defective. Is there any danger to plugging the CPU in my mobo and trying?

 

[myocardia]

None whatsoever. As long as the processor isn't magnetized, it can't harm a motherboard.

edit: Assuming that the processor and mobo have the same "pinout".

 

[Nil Einne]

You would think so wouldn't you? But actually you're wrong. I know someone who had this system with an A-XP. He was doing something (can't remember what) and when he put on the heatsink which was one of those typical old HSF style but with 3 clips each side it didn't attach properly, I believe only went on one of the clips on one side or something (I believe he did it inside the case). Anyway, the HSF fell off the comp died. It didn't physically damage the mobo AFAIK. And the CPU didn't look dead. But both were dead (why the mobo died is not sure but it seems likely it was the CPU, see below)

Of course, he didn't know what had died. He had a spare CPU and so used that and was able to tell the mobo was dead. He gave me the dead CPU but fortunately I never got round to trying it. When he got his new mobo, he got it running with the other CPU then changed to the dead CPU. And guess what? It killed the mobo. He RMAed the mobo as a DOA and I RMAed the CPU (he'd decided to buy a new CPU instead of waiting and gave me the old one). I didn't of course tell the people what happened to the CPU or that it was a mobo killer so I have no idea whether they tried it on a mobo which they killed. But it most definitely killed at least one mobo and probably two.

BTW, what's a magnetised processor?

P.S. And let's not go off-topic and discuss the ethics of RMAing something you know you killed.
P.P.S. I think it's extremely unlikely that you will get a killer CPU but it can happen. Why I don't know but I guess when you fry things currents can potentially go anywhere including places they're really not supposed to go. Given that P4s and A64s should never fry in this way it's probably much less likely to be a problem nowadays as well. However with a PSU blow out potentially it could have a similar effect so it could happen.
P.P.P.S. Assuming your friend stayed with Intel (I guess both processors are LGA775) and he has no qualms RMAing the mobo if he kills it then why not ask him if he can try the CPU? It's rather unlikely to kill the mobo but if it does there virtually no chance they will know it was killed by a killer CPU.

 

[Kwint Sommer]

The short answer is no. The slightly longer answer is it's possible but it would entail a large number of statistically unlikely events all occurring to that one processor so if you think you can win the lottery then you are likewise capable of killing your motherboard with this CPU. Personally I think the lottery is a tax on the statistically challenged and would use that processor.

 

[Nil Einne]

Originally posted by: Kwint Sommer
The short answer is no. The slightly longer answer is it's possible but it would entail a large number of statistically unlikely events all occurring to that one processor so if you think you can win the lottery then you are likewise capable of killing your motherboard with this CPU. Personally I think the lottery is a tax on the statistically challenged and would use that processor.

Pity I've never won the lotto. However I have to question your statistics. Specifically how exactly did you calculate the chance of getting a killer CPU? I personally think it's very unlikely but I do wonder whether whether it's as unlikely as winning the lotto. It's important to remember here we're not talking about a random processor here but a processor which we know may be damaged...

N.B. I would actually use that processor as well as I kind of indicated in my first post. However as I mentioned if your friend is willing to test it with an RMAable mobo, then why not?

 

[oynaz]

He had voided his warranty with some really funky cooling solutions on his mobo, so he went and upgraded to Conroe. So unfortunately I cannot get him to test it in his new mobo. I guess I will give it a try in mine.

 

[Maximilian]

Go buy a socket A motherboard, install an athlon thunderbird 1.4ghz and forget to put the heatsink/fan on. You will have one smoked cpu and probably mobo

In general though no, a cpu wont damage a mobo.

 

[oynaz]

I will give it a try then.

 

[oynaz]

Hmm, the computer starts OK, but Windows hangs while booting, both when starting normally and when running in safe mode. This is a bad sign I guess?

 

[myocardia]

It almost sounds as if your psu can't handle the extra load.

 

[oynaz]

My PSU can't handle going from a P4C 2,4 Ghz to a P4C 3,2 Ghz?

Thanks for the reply, but I find that implausible.

BTW, Memtest reports the CPU as a P4 2,8 Ghz, but it is labeled as 3,2 Ghz? Strange..

 

[myocardia]

Haha, I forgot about something. You aren't trying to run that 3.0 or 3.2C @ the same fsb, are you? If you've already set the BIOS back to a 200 Mhz fsb, I'd say that the cpu is defective. And yeah, a 3.2 Ghz cpu requires more power to run than a 2.4C. I had also forgotten that you had said that you were running your 2.4@3.0. I have a really, really bad memory.

 

[coolpurplefan]

Originally posted by: oynaz
My PSU can't handle going from a P4C 2,4 Ghz to a P4C 3,2 Ghz?

Thanks for the reply, but I find that implausible.

BTW, Memtest reports the CPU as a P4 2,8 Ghz, but it is labeled as 3,2 Ghz? Strange..

Was that a chip from eBay^

 

[oynaz]

Thx for the replies.
Let me put some things straight:

Ebay is not involved is this case in any way.
Overclocking is not involved in any way.

What I have is a 3,2 Ghz CPU which is reported as being 2,8 ghz by memtest86. My rig passes memtest flawlessly btw.
Windows XP hangs at boot, but the Ubuntu live CD is fine.

I think we can rule out the PSU as the culprit. It is a Chill 350 watt, and the rig has been rock stable until now.

 

[Maximilian]

If it ran fine for your friend, ask him what his PSU is, and ask him if there was any problems with it. If the answer is "a better psu than yours" and "no problems at all" its probably your PSU.

 

[oynaz]

He fried his mobo and PSU, and my PSU is much better than his.

The CPU idles at 85 C. I guess that might explain the problems.

 

[Zap]

The CPU running at 2.8GHz is the "failsafe" speed of the P4. Basically it is overheating.

BTW, IMO it is indeed possible, though unlikely, to kill a good motherboard with a bad CPU. Has happened to me with a socket 370 Celeron. A mobo/CPU combo was dead, so decided to test CPU in another mobo that was known good and tested just prior. No POST, no smoke, nothing exciting except it doesn't power on. Put the good CPU back in the "working" motherboard and it doesn't light up anymore. Still, would do it again because that's only one time I've seen it happen out of many times trying with testing other CPUs from dead systems.

 

[oynaz]

OK, the CPU is defective, and will be RMA'd. Thx for the replies everyone.

Hmm, does anyone know how to easiest contact Intel for an RMA request? I cannot find it on their website.