Suspected CPU or mobo failure, need 2nd opinion

[b1naryatr0hy]

Allow me to preface by saying that I have built about a dozen custom builds, so this isn't my first rodeo.

One of my custom PCs, which I've been using for about 4 years, decided to shut off quite randomly the other day. It's generally been running 24 hours per day so I'm not surprised that something finally failed. When attempting to start the computer up, it immediately shuts off in a couple hundred milliseconds or so. After thorough testing, I've come to the conclusion that the CPU is the culprit but I would like some 2nd opinions.

Problem:

PC shuts off immediately (about 250ms) after turning on

Debug steps:

Removed all peripherals, GPU, and RAM. - Problem persists

Removed PSU completely and tested it via the paperclip method. - PSU runs fine standalone

Tried a completely different, known working PSU just to be doubly sure. - Problem persists

Removed CPU from the mobo. - Runs okay, no longer shuts off instantly, i.e. PSU/mobo stays in the 'on' state

Reconnected CPU, tested again - Problem returns, shuts off instantly again

Double and triple checked all connections - Problem persists

I have no extra viable mobos or CPUs to do further testing.

Mobo: ASUS Rampage Extreme socket T (LGA 775)
PSU: Corsair CMPSU-750TX; (also tested w/ Rosewill RD450-2DB)
CPU: Intel Core 2 Duo E8600

My conclusion is that the CPU has failed. What do you all think?

 

[geofelt]

It is extremely rare for an Intel cpu to fail.
On general principles, I would suspect the motherboard first.

If either part is still under warranty, I would try to RMA that one first.

At this point, I would not spend any more trying to fix a setup that is close to obsolescence.

 

[b1naryatr0hy]

It is extremely rare for an Intel cpu to fail.
On general principles, I would suspect the motherboard first.

If either part is still under warranty, I would try to RMA that one first.

At this point, I would not spend any more trying to fix a setup that is close to obsolescence.

I can't imagine anything is covered under warranty, all components are several years old. It seems a shame to just scrap it all. Especially considering the motherboard still sells for ~$500 (new) on ebay. Both the CPU and mobo are admirable pieces of technology, even by today's standards. The E8600 is the last Core 2 Duo Intel ever released, and is capable of overclocking to 4.0Ghz+ stable.

 

[geofelt]

Times have changed.
The E6800 had a passmark rating of 2406.
The cheapest modern socket 1150 chip, the G1820 dual core haswell sells for $50 and is rated at 2918.
A inexpensive 1150 motherboard can be <$50.

If your motherboard truly sells for $500, it will pay you to find out if it is good or bad.
Look for your motherboard in used condition.
Then, filter by completed auctions.
In green, you will see the actual selling prices.

Perhaps buy a supported cpu on ebay to test out if it is your mobo or cpu.

 

[b1naryatr0hy]

Times have changed.
The E6800 had a passmark rating of 2406.
The cheapest modern socket 1150 chip, the G1820 dual core haswell sells for $50 and is rated at 2918.
A inexpensive 1150 motherboard can be <$50.

If your motherboard truly sells for $500, it will pay you to find out if it is good or bad.
Look for your motherboard in used condition.
Then, filter by completed auctions.
In green, you will see the actual selling prices.

Perhaps buy a supported cpu on ebay to test out if it is your mobo or cpu.

You make a good point. Perhaps I'm playing favorites since I haven't used a CPU that's noticeably superior. I checked the completed auctions for that mobo on ebay, it goes for an average of $300 (used.) I'll just take your advice and purchase the cheapest compatible CPU I can find so I can at least pinpoint the cause. Thanks for you help geofelt.

Edit: It looks like there tons of LGA 775 CPUs on ebay, some of which are less than the price of a gallon of gas. I'll post my findings after the CPU has arrived.

 

[b1naryatr0hy]

It is extremely rare for an Intel cpu to fail.

Based on the fact that it was the CPU that was the culprit, it would be wise to remember that everything has a 100% failure rate, given enough time.

The outcome doesn't surprise me anyhow, I've encountered more failed Intel CPUs in my time than I have failed motherboards.

 

[bobdude11]

I would pull the cooler off, clean it and the CPU up and apply Artic Silver, then reseat the cooler and see if that corrects the issue. It could very well just be an over heat issue. I have heard of older thermal paste losing its properties over time. Otherwise, I would go into the BIOS and reset it to the defaults (safe default values) in case it turns out to be some setting that was overlooked or forgotten about.