Liquid Cooling, fans, radiators and air flow. Fundamental question?

[tomas3man]

There is a popular trend for PC BUILDERS: who will put more heatsinks, fans, cooling system in one case. Don't you think that's crazy? For example, the AMD Ryzen 9 7950x generates about 95C/200F and needs a liquid cooling system that is much larger in size than the processor itself. Compared to a car engine, a car radiator is much smaller, and runs at a much higher temperature. A car engine runs at about 2000F or 4500F, while a processor needs 10x less, about 200F. Has everyone gone crazy and lost their minds? Have cooling equipment manufacturers come up with a conspiracy theory that tells people to build giant coolers, and lose money unnecessarily in the process. Is there different physics when it comes to the CPU? What is the issue here?

 

[PDifolco]

3 minutes ago, tomas3man said:

There is a popular trend for PC BUILDERS: who will put more heatsinks, fans, cooling system in one case. Don't you think that's crazy? For example, the AMD Ryzen 9 7950x generates about 95C/200F and needs a liquid cooling system that is much larger in size than the processor itself. Compared to a car engine, a car radiator is much smaller, and runs at a much higher temperature. A car engine runs at about 2000F or 4500F, while a processor needs 10x less, about 200F. Has everyone gone crazy and lost their minds? Have cooling equipment manufacturers come up with a conspiracy theory that tells people to build giant coolers, and lose money unnecessarily in the process. Is there different physics when it comes to the CPU? What is the issue here?

 

Difference is that as you say an engine can operate a 1500C+, but silicon can't stand more than 100C, so need relatively much more cooling to keep that low temps

Don't see the problem here

[TatamiMatt]

14 minutes ago, tomas3man said:

There is a popular trend for PC BUILDERS: who will put more heatsinks, fans, cooling system in one case. Don't you think that's crazy? For example, the AMD Ryzen 9 7950x generates about 95C/200F and needs a liquid cooling system that is much larger in size than the processor itself. Compared to a car engine, a car radiator is much smaller, and runs at a much higher temperature. A car engine runs at about 2000F or 4500F, while a processor needs 10x less, about 200F. Has everyone gone crazy and lost their minds? Have cooling equipment manufacturers come up with a conspiracy theory that tells people to build giant coolers, and lose money unnecessarily in the process. Is there different physics when it comes to the CPU? What is the issue here?

 

Well cars have all the air in the world moving at say 70mph through a super dense radiator, cpus do not generally move at 70mph while running and so dont have that luxury

 

Secondly, its a tiny thing producing so much heat that needs to stay super cool, vs a giant thing producing heat and not caring how hot it gets, if we wanted to keep engines under 100C, then we'd need massive radiators...but we dont, they run better hot, oil heats up and becomes less viscous and acts as a better lubricant, fuel air mix when hot burns more efficiently as its more vaporised and closer to flash point. CPUs running hot do the opposite, run slower, worse and get damaged

 

This is a comparsion of apples to oranges

 

EDIT: Also in the image, thats a custom loop, unnecessary for running, a cpu will generally be kept cool with a small heatsink and some fans, and keep in mind it is cooling more than one component as the gpu is also being cooled

 

This is an extreme example of apples to oranges

[DoctorNick]

13 minutes ago, tomas3man said:

There is a popular trend for PC BUILDERS: who will put more heatsinks, fans, cooling system in one case. Don't you think that's crazy? For example, the AMD Ryzen 9 7950x generates about 95C/200F and needs a liquid cooling system that is much larger in size than the processor itself. Compared to a car engine, a car radiator is much smaller, and runs at a much higher temperature. A car engine runs at about 2000F or 4500F, while a processor needs 10x less, about 200F. Has everyone gone crazy and lost their minds? Have cooling equipment manufacturers come up with a conspiracy theory that tells people to build giant coolers, and lose money unnecessarily in the process. Is there different physics when it comes to the CPU? What is the issue here?

 

 

The issue is that modern CPU's and GPU's are so packed with transistors from about 5nm in size and up currently. I found this article which seem fairly accurate:

https://videocardz.com/newz/amd-ryzen-7000s-ccd-reportedly-features-6-57-billion-transistors-58-more-than-zen3

If we take a Zen 3 cpu for example, its generating 1.25W/mm² at 105W TDP

[tomas3man]

On 3/26/2024 at 12:59 PM, DoctorNick said:

The issue is that modern CPU's and GPU's are so packed with transistors from about 5nm in size and up currently. I found this article which seem fairly accurate:

https://videocardz.com/newz/amd-ryzen-7000s-ccd-reportedly-features-6-57-billion-transistors-58-more-than-zen3

If we take a Zen 3 cpu for example, its generating 1.25W/mm² at 105W TDP

I do not agree with you all.

 

The car engine, burns fuel at about 4500F, then radiator, much smaller than car engine, cool the liquid in pipes to about 212F. Its about 20 times reduces heat temperature of water. Focus that engine radiator is smaller than average car engine.

 

Then look at a size of CPU and size of AIO, which is average 10 time bigger than CPU. And Temperature of CPU is about tjmax 200F and it is reduced to about 60F this is about 3 times. And AIO is much bigger to CPU.

 

Try imagine, a car, that has 12 fans and radiator 10 times bigger. There is no matter how many transistors is inside of CPU.

 

Look at info graphic, what happen if car is cooled like PC computer?

 

[TatamiMatt]

10 hours ago, tomas3man said:

I do not agree with you all.

 

The car engine, burns fuel at about 4500F, then radiator, much smaller than car engine, cool the liquid in pipes to about 212F. Its about 20 times reduces heat temperature of water. Focus that engine radiator is smaller than average car engine.

 

Then look at a size of CPU and size of AIO, which is average 10 time bigger than CPU. And Temperature of CPU is about tjmax 200F and it is reduced to about 60F this is about 3 times. And AIO is much bigger to CPU.

 

Try imagine, a car, that has 12 fans and radiator 10 times bigger. There is no matter how many transistors is inside of CPU.

 

Look at info graphic, what happen if car is cooled like PC computer?

 

Car radiators are also under massive pressure, water can heat itself up to what 400C? and not boil, meaning a massive temperature delta can be created, car radiators are also much thicker, have much more fin density and have much more air moving through them, think about putting your face in front of a full force pc fan, and sticking your head out the window going 70mph. They also have a lot more ways to exhaust heat, for one, the exhaust dumps a lot of hot gases out, meaning their heat energy doesnt join the system, the actual engine block is a giant chunk of metal, or basically a massive heatsink in itself so dissipates heat to the surroundings and also constantly gets fed its own, albeit minor amount of liquid and air cooling with gas flowing through the pipes and the fuel air mix injecting into the cynlinders will absorb heat (although they immediately reintroduce heat but the heat absorption will not really add any extra energy to the explosion and so overall slightly lower net heat)

[NorKris]

13 hours ago, tomas3man said:

I do not agree with you all.

thats the nice thing about reality, what we are saying checks out  

13 hours ago, tomas3man said:

 

Then look at a size of CPU and size of AIO, which is average 10 time bigger than CPU. And Temperature of CPU is about tjmax 200F and it is reduced to about 60F this is about 3 times. And AIO is much bigger to CPU.

i think ur forgetting that many ppl that water cools their pc want big (and many) rads cuz they want to run fans at such low speeds that u cant hear anything. 

[DoctorNick]

13 hours ago, tomas3man said:

I do not agree with you all.

 

The car engine, burns fuel at about 4500F, then radiator, much smaller than car engine, cool the liquid in pipes to about 212F. Its about 20 times reduces heat temperature of water. Focus that engine radiator is smaller than average car engine.

 

Then look at a size of CPU and size of AIO, which is average 10 time bigger than CPU. And Temperature of CPU is about tjmax 200F and it is reduced to about 60F this is about 3 times. And AIO is much bigger to CPU.

 

Try imagine, a car, that has 12 fans and radiator 10 times bigger. There is no matter how many transistors is inside of CPU.

 

Look at info graphic, what happen if car is cooled like PC computer?

I don't know enough about engine cooling to answer this, but still can't see how it's comparable to cooling a PC.

[TatamiMatt]

Also yes the fuel burns at 4500F, but heat transfer takes time, the otto cycle is only undergoing explosion and expansion once every 4 cycles, per cylinder, and the explosion is happening extremely quickly, yes the engine burns fuel at 4500F, but the oil in the engine only heats up to what 90C? where did all that 4500F go? Well, it wasnt sustained long enough to transfer heat, heat transfer relates to how long a temperature is applied, over what time and what specfic heat capacity the other material has. You can pass your finger over a candle flame and feel no heat as it hasnt resided in the heat long enough to make any heat transfer

[thrasher_565]

from gen to gen as the chips gets smaller and more packed in the hotter the cpu gets and the cooling plates cant keep up so its hard to compare that is why its confusing.

back in the day when we water cooled the i7920 and oced it to 4.0ish and did an sli of say 2x gtx 275 cards most would round 2 360 rads some times 3 rads and target at about 60c with 1200 rpm fans.

 

the newer stuff runs hotter so air cooled there hitting like 85c+ so under water a good temp would be say 70c the more rads you add the more demising return per dollar spent per c drop.

Edited March 30 by thrasher_565