What does it mean to "burn-in" a cpu and is it necessary?

[cmai]

see title,

Thanks,

cmai

 

[Wingznut]

Some people believe that if you run your cpu at at high temp or under a very high load for a period of time, it can "break in" the cpu and allow it to overclock better.

Reality is... Is that this is nothing more than a fable.

 

[dullard]

Small microscopic changes occur between a CPU and the heatsink during the first few hours of use. For example if you use Artic Silver (or similar product) to connect the CPU to the heatsink, the hot temperatures allow the Artic Silver to flow slightly (it expands at a higher temperature) and provide a better connection for heat transfer. Thus over time the CPUs temperature will decrease slightly - until all these effects have had a time to occur - and then the CPU temperature will stop dropping.

If you are using the CPU at the stock conditition, burn-in is meaningless. The slight CPU temperature change will have no effect on you. If you overclock then this is significant. Often you will get a maximum overclock with a new setup, but after several days of use, you will be able to overclock it a bit higher. And this has been proven over and over again - but the effect is quite minor so many people say it doesn't exist.

 

[Wingznut]

Originally posted by: dullard
Small microscopic changes occur between a CPU and the heatsink during the first few hours of use. For example if you use Artic Silver (or similar product) to connect the CPU to the heatsink, the hot temperatures allow the Artic Silver to flow slightly (it expands at a higher temperature) and provide a better connection for heat transfer. Thus over time the CPUs temperature will decrease slightly - until all these effects have had a time to occur - and then the CPU temperature will stop dropping.

If you are using the CPU at the stock conditition, burn-in is meaningless. The slight CPU temperature change will have no effect on you. If you overclock then this is significant. Often you will get a maximum overclock with a new setup, but after several days of use, you will be able to overclock it a bit higher. And this has been proven over and over again - but the effect is quite minor so many people say it doesn't exist.

Just to clarify, my comments were about the cpu silicon itself.

 

[Special K]

I've heard that it is used to test for early failures (even among cpus running at their rated speeds), as components will tend to fail either early on or late in their life. Stressing your system to the max right after it is built would expose any weak components, allowing an OEM to replace the part before shipping the PC out. Can anyone confirm or deny this?

 

[Macro2]

RE:"I've heard that it is used to test for early failures (even among cpus running at their rated speeds), as components will tend to fail either early on or late in their life. Stressing your system to the max right after it is built would expose any weak components, allowing an OEM to replace the part before shipping the PC out. Can anyone confirm or deny this?"

That's a system burn in. Typically, after building the system the builder will run the system for a set period of time, say 24 hours to see if it's stable. Some will run a series of tests, usually something they have put together on a CD, to test functionality.

Then he will ship it out.

Typically, components will fail within the first fews days to a month of use. After that the computer is less likely to fail for some time.

Burning in a CPU is typically an overclockers term. Likely has more to do with the flowing of the Heat sink compound as was previously stated.
What happened to perpetuate this idea was that someone would build a computer and it would fail to overclock. Then the person would kick back the overclock and run it a while. Then later, when they kicked it back up to the original overclock it would be stable. They thought this was due to some internal change or "burning in" of the chip itself.

Mac

 

[Davegod]

the FAQ on this is a pretty convincing "dont bother"; goop-settling notwithstanding - many goop instructions will actually say it takes somewhere between a day and a week to settle fully. Also iirc has some comment SpecialK
might find interesting about chip-makers cooking cpu to weed out the bad-uns.

i'd link it directly but all of anandtech is on uber slow-mo for me right now, and its just giving 404error

 

[HappyCracker]

Linky
The manufacturer does this already. Don't waste your time.