Ivy Bridge 3570K Testing, Opinions, Results, New Bios, 4.5Ghz At 1.236v

[Ferzerp]

I'm pretty sure there is a valid reason for putting an IHS. Probably it is more to protect the die from cracking. We're talking about heatsinks that weigh about 1KG clamped down to a piece of glass. I've seen lidless CPUs, handled them as well but they are mostly in laptops.

It is exactly this. The heat spreader makes something that is extremely fragile much more durable. If you were around in the exposed die era, you'll remember how many people chipped their chip with uneven force while installing a heatsink.

 

[notty22]

Exactly it's goal is to protect the die and transfer as much heat to the actual heatsink as possible. Put your finger on top of a cpu without any heatsink and you will see how fast heat is transferred to the surface of the heat spreader. Your fingerprint will be burned on there almost instantly.
What and why they do things slightly different in laptops is for other various reasons. Like , they don't use a socket in most cases.

People have gained a few or a very small % of cooling by removing Heat spreaders, but not always. They are there to move heat on to the heat sink. That can be done very efficiently. While adding protection to the die.

 

[Ferzerp]

Remember these days?

Look at the bottom left corner.

 

[Ferzerp]

People have gained a few or a very small % of cooling by removing Heat spreaders, but not always. They are there to move heat on to the heat sink. That can be done very efficiently. While adding protection to the die.

Not really. They *always* lower the maximum heat that can be transfered from the die to the heatsink.

If you have a poor heatsink, they will be of benefit as they are more mass to spread the heat to, but if you have a specialized (or really almost anything better than the stock one) cooler, they are a detriment. They trade heat dissipation for durability.

If you need some authority to say this, just look at the posted review about the spreaderless procs on macs.

 

[notty22]

Not really. They *always* lower the maximum heat that can be transfered from the die to the heatsink.

If you have a poor heatsink, they will be of benefit as they are more mass to spread the heat to, but if you have a specialized (or really almost anything better than the stock one) cooler, they are a detriment. They trade heat dissipation for durability.

If you need some authority to say this, just look at the posted review about the spreaderless procs on macs.

What I wrote is correct. While they are never going to transfer 100%, it can be very close. Which is why someone removing a heat spreader may not gain any cooling decrease. Because they could lose things like clamp pressure/ contact area could be worse etc. I don't need to read a Mac thread.

 

[Ferzerp]

I'm not trying to be a git here, but you're asserting that adding additional layers of discrete materials does not reduce the maximum possible heat dissipation?

 

[Absolute0]

I can do 5Ghz with 1.43v. 4.6 seems to be the sweet spot. Anything more and you have to go insane with the voltages.

Also i discovered my H80 has a partially broken mount on one side meaning my IBT results are probably incorrect

Whoa, that's what we've been wanting to hear. 1.43v doesn't sound too insane considering how many people do 1.5+v for benching on SB. Can you do any benches at 5 Ghz?

 

[notty22]

I'm not trying to be a git here, but you're asserting that adding additional layers of discrete materials does not reduce the maximum possible heat dissipation?

It's not there to dissipate. Consider it a shim. It's goal is to move heat on to a actual heatsink.

 

[Ferzerp]

Ok, there must be a misunderstanding here.

We are saying the following: In a situation where you can't get heat off the proc fast enough, you can get heat off faster by removing any extraneous intermediate layers.

What it sounds to me like you are claiming is that is an incorrect statement.

Am I correct here in my interpretation of your claim?

 

[Absolute0]

In my experience popping IHS's off of AMD processors, the extra layer of thermal paste and a few millimeters of metal getting between your heat source and your heatsink obviously does nothing to improve temperatures... I removed the IHS off of some AMD64 series and Opteron chips a while back and my load temps dropped just over 10c. A bunch of people were doing this at the time and removing the IHS resulted in load temp drops from 5-15c (this is when highly overclocked of course). Intel is slightly different, I think their IHS's make better contact and you probably wont' find the improvement to be as great. But the point is it would still be an improvement if you could theoretically do it right. Not really feasible with teh way Intels are made these days though.


That little IHS just gets in the way. Mounting a heatsink on a bare core gets more efficient heat transfer. How does extra thermal gunk and metal hep? If you put another bigger heat spreader on top of the IHS, would this help temperatures, by "spreading" the heat for the larger base of the heatsink? Obviously not.

The IHS is there, as mentioned, to protect the core.

 

[notty22]

Ok, there must be a misunderstanding here.

We are saying the following: In a situation where you can't get heat off the proc fast enough, you can get heat off faster by removing any extraneous intermediate layers.

What it sounds to me like you are claiming is that is an incorrect statement.

Am I correct here in my interpretation of your claim?

You have been trying to over-complicate this, and put words in my statements that I was not claiming.
My first post, first sentence.

Exactly it's goal is to protect the die and transfer as much heat to the actual heatsink as possible.

People have gained a few or a very small % of cooling by removing Heat spreaders, but not always. They are there to move heat on to the heat sink. That can be done very efficiently

The Heat spreader can be near 100%, I never said it made anything better but helps eliminate possible variables that would make cooling and production costs worse.
Please stop derailing this thread. I'm done.

 

[Stoneburner]

IS IVB expected in retail channels by next monday?

 

[Grooveriding]

I can do 5Ghz with 1.43v. 4.6 seems to be the sweet spot. Anything more and you have to go insane with the voltages.

Also i discovered my H80 has a partially broken mount on one side meaning my IBT results are probably incorrect

Those numbers sound pretty good, a bit less than what is generally used to get 5ghz on SB. 5ghz IB should be equal to about what, a 5.5 SB ?

The question is whether it's stable and what temperatures are like.

 

[HilbertSpace]

As a physicist, I gotta agree with Absolute0, Ferzerp, puppies04, etc. the IHS can only reduce the effective removal of heat generated by the die. Wikipedia has a good write up on interfacial thermal resistance which explains one aspect of it - http://en.wikipedia.org/wiki/Interfacial_thermal_resistance

And I don't think the IHS would be even close to 100% efficiency in transferring the heat to the heatsink. As a guess I'd go with 70-90% - which would depend on heat differential between the hot and cold side, along with a lot of other factors.

 

[QuantumPion]

As a physicist, I gotta agree with Absolute0, Ferzerp, puppies04, etc. the IHS can only reduce the effective removal of heat generated by the die. Wikipedia has a good write up on interfacial thermal resistance which explains one aspect of it - http://en.wikipedia.org/wiki/Interfacial_thermal_resistance

And I don't think the IHS would be even close to 100% efficiency in transferring the heat to the heatsink. As a guess I'd go with 70-90% - which would depend on heat differential between the hot and cold side, along with a lot of other factors.

As an engineer I agree with notty. The heat spreader does technically increase the thermal resistance between the CPU and heat sink. Theoretically, removing the heat spreader would improve your heat transfer rate. However that resistance is very small and in practice, compared to the added resistance due to not having perfect contact between the heat sink and the bare CPU, you could easily be worse off.

 

[chimaxi83]

As an engineer I agree with notty. The heat spreader does technically increase the thermal resistance between the CPU and heat sink. Theoretically, removing the heat spreader would improve your heat transfer rate. However that resistance is very small and in practice, compared to the added resistance due to not having perfect contact between the heat sink and the bare CPU, you could easily be worse off.

"Perfect contact" between the IHS and the core doesn't exist. The guys who lap heatsinks get much better contact from core to heatsink (or IHS to heatsink) then anything Intel does. Hence the frequent 10C drops.

Yes, I would agree that the resistance to heat transfer rate is small, but its still resisted by ANYTHING placed between the core and your cooling solution.

The IHS spreads heat, sure, but it does nothing to improve cooling capability. Its main purpose is to prevent core damage.

 

[blckgrffn]

"Perfect contact" between the IHS and the core doesn't exist. The guys who lap heatsinks get much better contact from core to heatsink (or IHS to heatsink) then anything Intel does. Hence the frequent 10C drops.

Yes, I would agree that the resistance to heat transfer rate is small, but its still resisted by ANYTHING placed between the core and your cooling solution.

The IHS spreads heat, sure, but it does nothing to improve cooling capability. Its main purpose is to prevent core damage.

I think notty is pointing out that 99% of folks are better off with the IHS in a sense that performance is much reliable and that heatsink tolerances can be much looser. That the core is better protected is also part of the reason it is there.

One would hope that Intel is doing a better job with that IHS than the vast majority of folks would do without it - including OEMs.

 

[notty22]

Many who build computers/hobbyists might not follow simple rules of tightening bolts in a square pattern. What do you think happens then, and the possibilities of problems and breakage would increase without that heat spreader sitting over the die.

 

[Stoneburner]

I haven't seen a good IHS argument here in a while

<--- gets popcorn ready.

 

[Grooveriding]

Many who build computers/hobbyists might not follow simple rules of tightening bolts in a square pattern. What do you think happens then, and the possibilities of problems and breakage would increase without that heat spreader sitting over the die.

I broke an AMD CPU back in the day doing exactly this. Chipped a small piece off the corner of the die I like the IHS for exactly this reason. I was nervous putting the blocks on my 680s because of the exposed die and memories of damaging one in the past

 

[chimaxi83]

Many who build computers/hobbyists might not follow simple rules of tightening bolts in a square pattern. What do you think happens then, and the possibilities of problems and breakage would increase without that heat spreader sitting over the die.

Yes, this is what most of us have been saying. Die protection, not better heat transfer.

 

[notty22]

Since it's more on topic. At one point didn't Hocp, try to test cpu temperature with a probe on the IHS surface or actual die, if there was not one there ? A temperature reading from software that relies on calibration on a unreleased cpu is partly what the reputation of IB prowess is going to based on ? I think we don't have all the facts to compare SB to IB and what might have changed.

 

[Ferzerp]

No one is arguing that a heat spreader doesn't make it more durable. (In fact, all of us saying it impedes heat transfer explicitly said it makes the cpu more durable).

Back, when heat sinks were primarily aluminum, if the heatspreader package had an overall thermal conductivity (counting the resistance of any interface material, etc), it actually did assist in heat transfer. Now though, even aluminum heatsinks use copper at the interface. A heat spreader made from molten silver that was poured directly on to the die *might* work better than applying a copper heatsink directly on to the die if there were no gaps. None of the other materials that conduct heat better than copper are really feasible to use, and remember, you create an additional junction between discrete layers when you add a heat spreader, so not only must the material conduct heat better, it must still conduct heat better once you take the inevitable gaps it creates in to account. The thing is, silver is only marginally better than copper at heat conduction.

I think someone mentioned graphene above. It you could apply it such that there were no gaps, then yes, that would make an effective heat spreader as well as graphene can conduct heat about 15 times better than copper.


edit: the funny thing is, we're all going all out on heat spreaders when the original poster has come back and said that his bracket for his cooler is damaged, so he's likely not making good contact, so the entire argument may be moot.

 

[chimaxi83]

Since it's more on topic. At one point didn't Hocp, try to test cpu temperature with a probe on the IHS surface or actual die, if there was not one there ? A temperature reading from software that relies on calibration on a unreleased cpu is partly what the reputation of IB prowess is going to based on ? I think we don't have all the facts to compare SB to IB and what might have changed.

I think they milled a channel into the IHS to put their probe into, to avoid uneven mounting of the heatsink.

 

[Khato]

the IHS can only reduce the effective removal of heat generated by the die.

I'd have to disagree with such a blanket statement. The IHS is only a detriment if it increases thermal resistance to the heatsink. Yes, I wouldn't be surprised if it currently does in most cases, or at best is merely on-par with a direct interface.

Given that the thickness of copper in the IHS is likely only around 1.5mm thick, its effectiveness in actually 'spreading' heat from the silicon wouldn't be that pronounced - this is part of the reason why the intel stock heatsink just has a circular contact area, making contact in the corners of the IHS doesn't really yield much if any benefit. However, even if an IHS merely doubles the effective heat transfer area it can still be on par with a direct interface if it can provide a better thermal interface to the silicon.

That's really what it all comes down to. Thermal interface materials vary from the 2-3 W/mK that you're likely to find on stock heatsinks to ~9 W/mK for enthusiast materials to the ~20 W/mK of Indigo Extreme... All of which are quite a bit lower than the 149 W/mK of silicon and 390 W/mK of pure copper. If you take the 3 W/mK figure and assume that a 0.05mm joint thickness is possible with heatsink while 0.025mm is possible with IHS and that the IHS lateral heat-spread effectively doubles heat conduction area then you get the following:

Direct contact: 3 W/mK * 0.00016m^2 / 0.00005m = 9.6W/K = 9.9K rise with a 95W load
IHS: 3 W/mK * 0.00016m^2 / 0.000025m = 19.2W/K = 4.95K rise with a 95W load
+ 3 W/mK * 0.00032m^2 / 0.00005 = 19.2W/K = 4.95K rise with a 95W load
= 9.9K rise with 95W load.

Yes, that it's exceedingly simplistic comparison, but it works well to demonstrate why it does make sense to use an IHS and why for non-enthusiast purposes it's not necessarily detrimental. If due to the increasing heat density of future process nodes Intel develops an even better interface between silicon and IHS, then the presence of an IHS could easily become a benefit in all cases.

Edit: Actually, the TIM Intel's using between silicon and IHS is far better than I thought - http://www.intel.com/technology/itj/2008/v12i1/1-materials/5-solder.htm According to that, the silicon die is effectively soldered to the IHS with Indium, which has a thermal conductivity of 87 W/mK. The date on the article is February 2008 - has anyone actually removed their IHS on an Intel processor and had positive results since then?