News AMD Ryzen 8700G delidded – runs up to 25 degrees Celsius cooler and up to 17% faster

[Admin]

Delidding an AMD Ryzen 8700G and using Liquid Metal TIM can reduce core temperatures by up to 25 degrees Celsius and improve performance by up to 17%.

AMD Ryzen 8700G delidded – runs up to 25 degrees Celsius cooler and up to 17% faster : Read more

 

[yeyibi]

Δ25 Cº means that AMD packaging design is massively incompetent.

 

[Kamen Rider Blade]

Δ25 Cº means that AMD packaging design is massively incompetent.

The IHS was meant to be designed for backwards compatibility with existing AM4 HeatSinks.

The bad part was the cut-outs that led to less surface area for heat removal.

 

[Notton]

Δ25 Cº means that AMD packaging design is massively incompetent.

Or it's a laptop chip with TJmax of 95C, and only hitting 85C under heavy load.
I figure AMD was too cheap to do the mating with iridium.

Curiously, the 8840HS has aTJmax of 100C.

 

[The Historical Fidelity]

The IHS was meant to be designed for backwards compatibility with existing AM4 HeatSinks.

The bad part was the cut-outs that led to less surface area for heat removal.

No the bad part is that the IHS is much thicker than the AM4 IHS which degrades thermal conductivity. The cut-outs actually do not degrade heat removal nearly as much in this case since the monolithic die is far away from these areas. The math formula for thermal conductivity states the thickness of the material between the heat source and cooler cold plate greatly affects the amount of heat that can be transferred, with thin material superior to thick. This is also why the cut-outs are not important because the effective thickness of the material between point a (edge of top of die) to point b (edge of top of IHS at cut-out) is so thick that minimal heat energy will travel there compared to the IHS directly above the die. The thickness of the IHS directly above the die has a maximal effect on heat removal in this case.

 

[TerryLaze]

Δ25 Cº means that AMD packaging design is massively incompetent.

Everything is always a matter of cost, these APUs are expensive enough as they are, making them even more expensive (and draw a ton more power) isn't worth it.
I mean derbauer even shows the differences so you can see that their packaging design skills are fine, they just didn't choose to implement them in this APU.

 

[Tom Sunday]

I religiously and always visit all our local computer shows and talking to scores of people behind and fronting the hundreds of folding tables. Even engaging conversations carried in the long line of the excellent Costco style hot-dogs served in the rear of the show. It’s a paradise for conversation and contact and meeting the ‘man on the street’ with real live visceral and eye to eye contact! I am yet to meeting anyone who “Delidded” their CPU!”

 

[Kamen Rider Blade]

No the bad part is that the IHS is much thicker than the AM4 IHS which degrades thermal conductivity. The cut-outs actually do not degrade heat removal nearly as much in this case since the monolithic die is far away from these areas. The math formula for thermal conductivity states the thickness of the material between the heat source and cooler cold plate greatly affects the amount of heat that can be transferred, with thin material superior to thick. This is also why the cut-outs are not important because the effective thickness of the material between point a (edge of top of die) to point b (edge of top of IHS at cut-out) is so thick that minimal heat energy will travel there compared to the IHS directly above the die. The thickness of the IHS directly above the die has a maximal effect on heat removal in this case.

But with thicker IHS, you can store more heat inside the IHS before you have to remove it.

They went and created a thicker IHS to maintain backwards compatibility, but the cut-outs significantly removed surface area for them to conduct heat away.

Those are the major issues I have with the current setup.

 

[rluker5]

I religiously and always visit all our local computer shows and talking to scores of people behind and fronting the hundreds of folding tables. Even engaging conversations carried in the long line of the excellent Costco style hot-dogs served in the rear of the show. It’s a paradise for conversation and contact and meeting the ‘man on the street’ with real live visceral and eye to eye contact! I am yet to meeting anyone who “Delidded” their CPU!”

I won't count, but I started delidding with my 4770k in 2013. The temp I gained was less than 25c with the CPU that popularized delidding due to "pigeon poop". LGA 1150 CPUs are so easy to do.

I blame that AM5 IHS. It is too chonky. AM4 IHS was a real good one. AMD should have made people just buy adapter kits of washers. Probably would have been $5 for name brand ones.

 

[The Historical Fidelity]

But with thicker IHS, you can store more heat inside the IHS before you have to remove it.

They went and created a thicker IHS to maintain backwards compatibility, but the cut-outs significantly removed surface area for them to conduct heat away.

Those are the major issues I have with the current setup.

Thermodynamics does not care that you think the cut-outs affect thermal conduction to any relevant degree and I demonstrated it to you mathematically in my previous point. And you actually do not want an IHS that is thick enough where the amount of heat generated by the die is greater than the IHS’s ability to conduct the heat to the cold plate. Besides, you would need a 6 inch thick IHS to have enough thermal capacity to last a couple of minutes at full tilt before the die thermal fuses. The key is to get the dies heat moved to the cold plate as quickly as possible because the IHS is the rate limiting step, IE an inefficient IHS at transferring heat to the cooler is the biggest hurdle to controlling heat. This is why direct die cooling is so much better than having any kind of IHS between the die and cold plate. IHS’s are there to protect the die from damage, not to enhance cooling. Many CPU’s back in the day had bare dies, and consumers had a hard time installing coolers on them without chipping or cracking the dies. Laptop CPU’s and GPU’s have never used IHS’s because consumers aren’t meant to be the ones installing coolers on them. Believe me, if IHS’s had any benefit to cooling said dies (like a 500 watt capable strix 4090 comes to mind as a die that needs all the tricks to cool), then they would put them on the dies. But they don’t, because IHS’s reduce thermal transfer out of the die and into the cooler.

 

[Kamen Rider Blade]

Steady state is reached quite rapidly so more material does not equal any real benefit. You would need a 6 inch thick IHS to last a couple of minutes at full tilt before the die thermal fuses. The key is to get the dies heat moved to the cold plate as quickly as possible because the IHS is the rate limiting step, IE an inefficient IHS at transferring heat to the cooler is the biggest hurdle to controlling heat. This is why direct die cooling is so much better than having any kind of IHS between the die and cold plate. IHS’s are there to protect the die from damage. Many CPU’s back in the day had bare dies and consumers had a hard time installing coolers on them without chipping or cracking the dies. Laptop CPU’s and GPU’s have no IHS’s because consumers aren’t meant to be the ones installing coolers on them. Believe me, if IHS’s had any benefit to cooling a 500 watt capable strix and other top shelf 4090s, then they would put them on the dies.

I know, I was around for those Direct Die days.

That being said, Direct Die isn't worth the RMA troubles for average DIY or the techs who work at OEM/ODM shops who assemble PC's, so there's that.

And because we have the IHS that we have, I was very upset when AMD took away surface area to conduct heat away with.

I have my alternate IHS idea that I want AMD to adopt, but that requires them to be willing to change the IHS.

Given the "Sunk Cost" of the current IHS, I don't think they'll change until we move to a brand new Socket AM6.

 

[TerryLaze]

Thermodynamics does not care that you think the cut-outs affect thermal conduction to any relevant degree and I demonstrated it to you mathematically in my previous point. And you actually do not want an IHS that is thick enough where the amount of heat generated by the die is greater than the IHS’s ability to conduct the heat to the cold plate. Besides, you would need a 6 inch thick IHS to have enough thermal capacity to last a couple of minutes at full tilt before the die thermal fuses. The key is to get the dies heat moved to the cold plate as quickly as possible because the IHS is the rate limiting step, IE an inefficient IHS at transferring heat to the cooler is the biggest hurdle to controlling heat. This is why direct die cooling is so much better than having any kind of IHS between the die and cold plate. IHS’s are there to protect the die from damage, not to enhance cooling. Many CPU’s back in the day had bare dies, and consumers had a hard time installing coolers on them without chipping or cracking the dies. Laptop CPU’s and GPU’s have never used IHS’s because consumers aren’t meant to be the ones installing coolers on them. Believe me, if IHS’s had any benefit to cooling said dies (like a 500 watt capable strix 4090 comes to mind as a die that needs all the tricks to cool), then they would put them on the dies. But they don’t, because IHS’s reduce thermal transfer out of the die and into the cooler.

All the things you say are true, the thing though is that they only apply to extremes, or rather that's the only time where they matter, if the cooling is too underpowered for the CPU (you want to do a high overclock) then all the things you say make sense.
But on a simple system where you get maybe a second of high boost because something ran in the background that thick IHS is gonna keep the fan from revving up for a sec and for full load on a simple system it just doesn't matter since the cooler will still draw all of the heat, it doesn't matter to the normal end user if the CPU is 90 (with cheap cooling) or 70 degrees (with expensive cooling) .

 

[deesider]

Thermodynamics does not care that you think the cut-outs affect thermal conduction to any relevant degree and I demonstrated it to you mathematically in my previous point. And you actually do not want an IHS that is thick enough where the amount of heat generated by the die is greater than the IHS’s ability to conduct the heat to the cold plate. Besides, you would need a 6 inch thick IHS to have enough thermal capacity to last a couple of minutes at full tilt before the die thermal fuses. The key is to get the dies heat moved to the cold plate as quickly as possible because the IHS is the rate limiting step, IE an inefficient IHS at transferring heat to the cooler is the biggest hurdle to controlling heat. This is why direct die cooling is so much better than having any kind of IHS between the die and cold plate. IHS’s are there to protect the die from damage, not to enhance cooling. Many CPU’s back in the day had bare dies, and consumers had a hard time installing coolers on them without chipping or cracking the dies. Laptop CPU’s and GPU’s have never used IHS’s because consumers aren’t meant to be the ones installing coolers on them. Believe me, if IHS’s had any benefit to cooling said dies (like a 500 watt capable strix 4090 comes to mind as a die that needs all the tricks to cool), then they would put them on the dies. But they don’t, because IHS’s reduce thermal transfer out of the die and into the cooler.

That's all fine and dandy, but bear in mind that in Der8auer's testing he changed the TIM then placed the IHS back on. So whether or not the IHS is 'too thick', a 10 degree improvement was obtained simply by swapping the TIM to a better one.

 

[bit_user]

bear in mind that in Der8auer's testing he changed the TIM then placed the IHS back on. So whether or not the IHS is 'too thick', a 10 degree improvement was obtained simply by swapping the TIM to a better one.

I wonder how the longevity of his TIM compares to the stock TIM. Also, I wonder how much he reduced the gap between the die and the IHS, assuming he didn't replace the adhesive holding the IHS to the PCB - that probably accounted for some of the gains.

 

[deesider]

I wonder how the longevity of his TIM compares to the stock TIM. Also, I wonder how much he reduced the gap between the die and the IHS, assuming he didn't replace the adhesive holding the IHS to the PCB - that probably accounted for some of the gains.

The 10 degree improvement was from using Kryosheet - which is a thermal pad. Not the best in thermal performance but known to be very long lasting, and reusable. Suggests that AMD could have done much better.

 

[bit_user]

The 10 degree improvement was from using Kryosheet - which is a thermal pad. Not the best in thermal performance but known to be very long lasting, and reusable. Suggests that AMD could have done much better.

It's a new form of graphene-based thermal pad (i.e. Z-oriented), so I wouldn't consider that typical of a thermal pad.

Probably the only thing AMD could've done on that performance level would've been to use solder, which they probably skipped for cost reasons.

 

[The Historical Fidelity]

That's all fine and dandy, but bear in mind that in Der8auer's testing he changed the TIM then placed the IHS back on. So whether or not the IHS is 'too thick', a 10 degree improvement was obtained simply by swapping the TIM to a better one.

Yes, I forgot AMD ivy-bridged the 8000 series APUs by using thermal paste instead of solder.

 

[deesider]

It's a new form of graphene-based thermal pad (i.e. Z-oriented), so I wouldn't consider that typical of a thermal pad.

Probably the only thing AMD could've done on that performance level would've been to use solder, which they probably skipped for cost reasons.

No, Kryosheet isn't better than thermal paste: https://www.techpowerup.com/review/thermal-grizzly-kryosheet-amd-gpu/5.html

 

[Eximo]

I figure AMD was too cheap to do the mating with iridium.

Iridium would be pretty expensive. If I recall that is step up in cost from Platinum. Rhodium falls in there somewhere too.

Indium is the common solder material.

 

[bit_user]

No, Kryosheet isn't better than thermal paste: https://www.techpowerup.com/review/thermal-grizzly-kryosheet-amd-gpu/5.html

At first glance, it might not seem that impressive. However, when you look a bit more closely, it does start to emerge as a serious contender:

"... for 300 W and above, the temperatures are fine, and at maximum heat load, the KryoSheet actually achieves the best temperatures of all our TIMs, by a small margin though.
...
It's possible that my first cut of the KryoSheet was a little bit too small, or it moved a bit during installation for the first run, so I recommend you don't cut it to the exact size of the die, but leave a little bit of overhang—the capacitors are not that close.
...
the "Hotspot Temperature" results show a little bit bigger differences between the various pastes at maximum heat load. It's still not a night-and-day difference, but I think 5°C is something that you can start appreciating, especially on a higher powered card like the RX 7900 XTX."
​

Thanks for sharing! It's been a while since I last searched for KryoSheet reviews.

I am a little concerned about how hard it is to work with. If you remember the leds from like 0.3 mm mechanical pencils, I think it's brittle like that.

I'm also concerned about mounting force, and I worry this could limit its supposed reusability. You want to clamp it hard enough to make good contact, but I think this should also crush some of the graphene structures. Not clamping it hard enough could leave some air gaps, but clamping it too hard could actually hurt performance. That said, I need to read more, and will be paying closer attention to it, in the future.

I'm curious to hear @The Historical Fidelity 's take on these points.

 

[Kamen Rider Blade]

At first glance, it might not seem that impressive. However, when you look a bit more closely, it does start to emerge as a serious contender:

​

"... for 300 W and above, the temperatures are fine, and at maximum heat load, the KryoSheet actually achieves the best temperatures of all our TIMs, by a small margin though.​

...​

It's possible that my first cut of the KryoSheet was a little bit too small, or it moved a bit during installation for the first run, so I recommend you don't cut it to the exact size of the die, but leave a little bit of overhang—the capacitors are not that close.​

...​

the "Hotspot Temperature" results show a little bit bigger differences between the various pastes at maximum heat load. It's still not a night-and-day difference, but I think 5°C is something that you can start appreciating, especially on a higher powered card like the RX 7900 XTX."​

​

Thanks for sharing! It's been a while since I last searched for KryoSheet reviews.

I am a little concerned about how hard it is to work with. If you remember the leds from like 0.3 mm mechanical pencils, I think it's brittle like that.

I'm also concerned about mounting force, and I worry this could limit its supposed reusability. You want to clamp it hard enough to make good contact, but I think this should also crush some of the graphene structures. Not clamping it hard enough could leave some air gaps, but clamping it too hard could actually hurt performance. That said, I need to read more, and will be paying closer attention to it, in the future.

I'm curious to hear @The Historical Fidelity 's take on these points.

It's a "Use Once Only" kind of Graphene Sheet.

Once it's in, you don't mess with it, it's great for certain applications.

e.g. (North/South) Bridges / Media Connector Hubs, devices that you don't want to have to re-paste because they're a PitA to do so.