[xander89]

Originally Posted by BeerHunter

does it matter how hot it runs? I saw a review which was benchmarking at 5Ghz and over 100C but does that matter? Why or why not?

running your chip at high temps will contribute to CPU degredation and ultimately shorten the lifespan of you CPU

[EarthDog]

It is OK. The TJmax is 105C (where it throttles down to save itself) vs SB that was 95C.

As always, the cooler the better.

[bmwbaxter]

Originally Posted by BeerHunter

does it matter how hot it runs? I saw a review which was benchmarking at 5Ghz and over 100C but does that matter? Why or why not?

It matters because too high of temps can cause stability issues and if it gets hot enough the CPU will throttle itself to prevent damage which will have a major impact on performance. Also if you are running at 100c you could easily get a temp spike that will cause your computer to BSOD.

Definitely not the desired result.

[BeerHunter]

The 920 I have gets to 75C sometimes on water and never had issues. I really don't care as long as it's stable and WC for noise purposes mainly especially with loud video cards. Anyway good info - I will try and keep it lower than 105C.

[EarthDog]

I wouldnt go higher than the mid 80s when stress testing personally. Keep WELL away from 105C, just as you kept well away from 100C (had wrong # up there, sorry).

[Janus67]

I would set 85C to be an approximate temp limit on the CPU, I like to keep my CPUs about 20C under TJMax at 100% load to do my best to prevent any sort of degration

[TNM]

I am curious now on how the design is of the new IHS to avoid multiple mounts of a heatsink from giving problems with air pockets in the TIM?

Consider that you mount a new heatsink. You tighten it up well.
Unless the TIM is of a different design than anything else I have seen, you will potentially squeeze it a bit (I mean, you actually want to do so I think) and some of it will have to go out to the side.

Remove the heatsink and the pressure, and I would guess the IHS "bounces back" giving you air pockets between the IHS and the TIM/cpu die.

I this could get even worse I guess if you just squeeze hard on the middle of the IHS with your finger and the heatsink would always eventually stop against the side walls of the IHS (depending of course on exactly how tall these are vs. the die, I am sure it is practically the same, but is it accurate enough?).

This would eventually leave it to the TIM you put on top of the IHS to make sure the IHS gets "pushed down enough" to remove any air pockets (potentially benefitting the use of rather thick TIM like arctic silver or ceramique?) if that is even possible on a second mount.

Could it be that the second mount of a heatsink will never ever get the same quality in heat transfer as the first? Just like reusing the TIM on a heatsink multiple times?

Yes, I realize the IHS most likely is is pretty stiff as well (I have not seen the IB one, but older IHS's I have played with was not easily bendable), but I assume there is some microscopic bending of it when you tighten a heatsink well on top of it so the center part will get squeezed down a bit.

[ehume]

Originally Posted by TNM

I am curious now on how the design is of the new IHS to avoid multiple mounts of a heatsink from giving problems with air pockets in the TIM?

Consider that you mount a new heatsink. You tighten it up well.
Unless the TIM is of a different design than anything else I have seen, you will potentially squeeze it a bit (I mean, you actually want to do so I think) and some of it will have to go out to the side.

Remove the heatsink and the pressure, and I would guess the IHS "bounces back" giving you air pockets between the IHS and the TIM/cpu die.

I this could get even worse I guess if you just squeeze hard on the middle of the IHS with your finger and the heatsink would always eventually stop against the side walls of the IHS (depending of course on exactly how tall these are vs. the die, I am sure it is practically the same, but is it accurate enough?).

This would eventually leave it to the TIM you put on top of the IHS to make sure the IHS gets "pushed down enough" to remove any air pockets (potentially benefitting the use of rather thick TIM like arctic silver or ceramique?) if that is even possible on a second mount.

Could it be that the second mount of a heatsink will never ever get the same quality in heat transfer as the first? Just like reusing the TIM on a heatsink multiple times?

Yes, I realize the IHS most likely is is pretty stiff as well (I have not seen the IB one, but older IHS's I have played with was not easily bendable), but I assume there is some microscopic bending of it when you tighten a heatsink well on top of it so the center part will get squeezed down a bit.

Now that is quite a thought. Makes sense. They'd really have to tighten up the IHS/CPU join to keep that from happening.

[diaz]

Originally Posted by EarthDog

I wouldnt go higher than the mid 80s when stress testing personally. Keep WELL away from 105C, just as you kept well away from 100C (had wrong # up there, sorry).

Originally Posted by Janus67

I would set 85C to be an approximate temp limit on the CPU, I like to keep my CPUs about 20C under TJMax at 100% load to do my best to prevent any sort of degration

You guys worried the chip will degrade over time? It shouldn't since it is protected at 105C.. Its not going to start melting, the melting point is much higher than that. Silicon melts at 1400C for example.. of course there are other materials used on the chip, but just saying that if they engineered it to work at 104C and protect itself at 105C, then it will be fine.

Unless someone here has concrete evidence that high temps causes CPU degradation to many people? The only chips I have seen destroyed are ones with the safeguards/throttling turned off and chips pushed WAY beyond their engineered realm of operation.

A barrier I would see is if you set it to 104C, and then your ambient temps increase on certain days. So you'd want your max ambient delta to be considered. So something around 90C, expecting a ~+10 fudge factor on your ambient.

Another situation is cooling degradation. If your PC collects dust, with time you might gain some temps, so keep an eye on temps and dust PC often

[xander89]

Originally Posted by diaz

You guys worried the chip will degrade over time? It shouldn't since it is protected at 105C.. Its not going to start melting, the melting point is much higher than that. Silicon melts at 1400C for example.. of course there are other materials used on the chip, but just saying that if they engineered it to work at 104C and protect itself at 105C, then it will be fine.

Unless someone here has concrete evidence that high temps causes CPU degradation to many people? The only chips I have seen destroyed are ones with the safeguards/throttling turned off and chips pushed WAY beyond their engineered realm of operation.

A barrier I would see is if you set it to 104C, and then your ambient temps increase on certain days. So you'd want your max ambient delta to be considered. So something around 90C, expecting a ~+10 fudge factor on your ambient.

Another situation is cooling degradation. If your PC collects dust, with time you might gain some temps, so keep an eye on temps and dust PC often

its also going to cause stability issues, i doubt you would get a chip that can run at 100 c under prime that would stay stable. I would assume most chips are going to run into stability issues when hitting the high 80's/ early 90s

[Janus67]

Originally Posted by diaz

You guys worried the chip will degrade over time? It shouldn't since it is protected at 105C.. Its not going to start melting, the melting point is much higher than that. Silicon melts at 1400C for example.. of course there are other materials used on the chip, but just saying that if they engineered it to work at 104C and protect itself at 105C, then it will be fine.

Unless someone here has concrete evidence that high temps causes CPU degradation to many people? The only chips I have seen destroyed are ones with the safeguards/throttling turned off and chips pushed WAY beyond their engineered realm of operation.

A barrier I would see is if you set it to 104C, and then your ambient temps increase on certain days. So you'd want your max ambient delta to be considered. So something around 90C, expecting a ~+10 fudge factor on your ambient.

Another situation is cooling degradation. If your PC collects dust, with time you might gain some temps, so keep an eye on temps and dust PC often

From reading reports of SB users that kept their temps/voltages too high to have degradation issues is my only source. I've always kept my chips as cool as I could and never put a ton of load into them (beyond benchmarking which I try to do SubZero and a quick stability test + gaming)

[EarthDog]

Originally Posted by diaz

You guys worried the chip will degrade over time? It shouldn't since it is protected at 105C.. Its not going to start melting, the melting point is much higher than that. Silicon melts at 1400C for example.. of course there are other materials used on the chip, but just saying that if they engineered it to work at 104C and protect itself at 105C, then it will be fine.

Unless someone here has concrete evidence that high temps causes CPU degradation to many people? The only chips I have seen destroyed are ones with the safeguards/throttling turned off and chips pushed WAY beyond their engineered realm of operation.

A barrier I would see is if you set it to 104C, and then your ambient temps increase on certain days. So you'd want your max ambient delta to be considered. So something around 90C, expecting a ~+10 fudge factor on your ambient.

Another situation is cooling degradation. If your PC collects dust, with time you might gain some temps, so keep an eye on temps and dust PC often

Lulz, Im not worried about it melting!!

I wouldnt be too worried about degredation with the warm temps personally. But with stability... the cooler the better.

http://hwbot.org/forum/showthread.php?t=45302

[diaz]

Originally Posted by Janus67

From reading reports of SB users that kept their temps/voltages too high to have degradation issues is my only source. I've always kept my chips as cool as I could and never put a ton of load into them (beyond benchmarking which I try to do SubZero and a quick stability test + gaming)

What are the symptoms they described as CPU degradation?

[EarthDog]

Originally Posted by diaz

What are the symptoms they described as CPU degradation?

Not sure what "they" said, but degredation on these things that I have seen are, higher voltage needed for the same overclock, unable to reach the peak clocks anymore...etc. Those are pretty typical symptoms of a degraded chip.

[diaz]

Originally Posted by EarthDog

Not sure what "they" said, but degredation on these things that I have seen are, higher voltage needed for the same overclock, unable to reach the peak clocks anymore...etc. Those are pretty typical symptoms of a degraded chip.

I see... maybe a degraded motherboard filter section? Because silicon is 0 or 1, vs filter section capacitors can degrade over time or if pushed too hard (voltage), or beyond their working temperature..

[EarthDog]

Highly doubtful its the mobo. I have seen people drop a degraded CPU in another board with the same results.

[diaz]

Ok, point taken.. Thanks for the info

[bmwbaxter]

Degradation can happen on chips that have only been run subzero, so it is not always temps that degrade chips. Once voltage is added you can start to degrade your CPU even below it's TJmax.

[jason4207]

If you never really stress your chip much then electromigration occurs much more slowly. When running stress tests you get much higher current which is when the most "damage" occurs.

Lower temps allow electrons to flow more freely and thus electromigration is lower for a given load. But under extreme low temps we push extreme loads (more voltage and current). Push too far and some of those traces pop like fuses at any temp.

[bmwbaxter]

Originally Posted by jason4207

Lower temps allow electrons to flow more freely and thus electromigration is lower for a given load. But under extreme low temps we push extreme loads (more voltage and current). Push too far and some of those traces pop like fuses at any temp.

Like running 2.2V through an FX-8150?