Thinner LPDDR5x from Samsung

[NotEntirelyConfused]

AT had an article today about how thinner LPDDR5x modules would improve smartphones by allowing them to be thinner, or by allowing for more airflow and thus better heat dissipation.

Is "airflow" really a thing in phones? Maybe convection creates a little bit I guess? It occurs to me that if you have a RAM package sitting on top of your processor, it's acting as a tiny insulator, and so the thinner it gets, the less insulation, thus better heat transfer to air (or a heat spreader or whatever). I naively think that that might be more significant than the air gap above the CPU (if indeed such even exists - it won't if there's a spreader). But I really know way too little about this.

Can anyone with more knowledge explain?

 

[Cmaier]

AT had an article today about how thinner LPDDR5x modules would improve smartphones by allowing them to be thinner, or by allowing for more airflow and thus better heat dissipation.

Is "airflow" really a thing in phones? Maybe convection creates a little bit I guess? It occurs to me that if you have a RAM package sitting on top of your processor, it's acting as a tiny insulator, and so the thinner it gets, the less insulation, thus better heat transfer to air (or a heat spreader or whatever). I naively think that that might be more significant than the air gap above the CPU (if indeed such even exists - it won't if there's a spreader). But I really know way too little about this.

Can anyone with more knowledge explain?

Airflow isn’t a thing unless there’s a fan that is producing turbulent flow.

As for dissipating CPU heat through the RAM, that’s really not what you want to do - you’re making the RAM hotter and RAM doesn’t want to be hot.

 

[NotEntirelyConfused]

Airflow isn’t a thing unless there’s a fan that is producing turbulent flow.

What I figured, though I still wonder about convection.

As for dissipating CPU heat through the RAM, that’s really not what you want to do - you’re making the RAM hotter and RAM doesn’t want to be hot.

Well obviously, but isn't that what's actually happening? Apple at least is mounting RAM directly on the CPU. So while some heat may escape through the back side (much less, presumably, because you have the package, PCB, and maybe other stuff acting as insulator), most is going through the front/top. Which is to say, through the RAM. Right?

 

[Cmaier]

What I figured, though I still wonder about convection.


Well obviously, but isn't that what's actually happening? Apple at least is mounting RAM directly on the CPU. So while some heat may escape through the back side (much less, presumably, because you have the package, PCB, and maybe other stuff acting as insulator), most is going through the front/top. Which is to say, through the RAM. Right?

Convection won’t be a factor. Too small an effect, and you’d really want an enclosed system like a pipe cooler if you were going to try and rely on convection.

Apple mounts RAM on top in the A-series. I assume most of the heat transfer is out the back, through the board though. I’d have to run a simulation. But there are insulation layers between the CPU and the RAM which don’t make good thermal conductors, so it would be very hard to rely on cooling upward. I assume the board is mounted with the package’s bottom side on the back surface of the phone, and transmitting heat that direction is better than through the OLED screens.

 

[NotEntirelyConfused]

Thank you, I didn't realize cooling through the board is practical.

So the article in AT was mostly nonsense, talking about the cooling benefits of thinning the RAM. Sigh. That site used to be really good. :-(

 

[dada_dave]

Thank you, I didn't realize cooling through the board is practical.

So the article in AT was mostly nonsense, talking about the cooling benefits of thinning the RAM. Sigh. That site used to be really good. :-(

To drive content they do a lot of just reposting of industry PR tech presentations - same as a lot of sites. That can sometimes still be interesting, but isn’t always … true. Or like in this case can be true to a small extent but isn’t really true in the full context.

This isn’t an excuse but unfortunately it’s how we’ve structured the internet. Sites feel they have to go this to survive and adding original material, ie the author’s own thoughts and experience is expensive. Reposting is cheap, gets the clicks and keeps people visiting regularly which helps SEO, brings in the ad revenue that the parent company demands for the cost they want.

Again, not defending this practice since this justifies the continued enshittification of content, just trying to explain that even once great sites like Anandtech are not immune to gravity.