Has anybody ever stacked two CPU coolers? First one fitted normally, then the second welded on top of it. Theoretically, you have twice the cooling, if it conducts through the first fast enough. I'm referring to the type with the fan on the side.
Stacked TECs are an old technology. They work at some level if you're careful, but the inefficiency of the earlier stages produces a huge heat load on the later ones, so the available delta-T is generally disappointing.
Cheers
Phil Hobbs
-- Dr Philip C D Hobbs Principal Consultant ElectroOptical Innovations LLC / Hobbs ElectroOptics Optics, Electro-optics, Photonics, Analog Electronics Briarcliff Manor NY 10510 http://electrooptical.net http://hobbs-eo.com
If you've got two of the same size TECs, then you might do better to get a bigger heat sink and run them in parallel. (not series stacked) More current rather than more voltage.
George H.
I'm not using TECs. Just a heatsink with heatpipes, and a fan.
seems odd.
Yeah, if. I doubt that it would, often the fins are tapered.
Just get a taller one that has heat pipes, then conduction is less of an issue.
-- Jasen.
Seems it might work.
The top of the first is hot to touch.
They're not.
Not available and/or expensive.
Stacking CPU coolers will have a huge impedance mismatch on the second one - essentially wasting most of its capability.
It is antisocial to operate a fast PC outside an enclosure other than for testing because it is a broadband emitter of RF interference to GHz.
You can get oversize heatsinks using heatpipes to shift more heat from the CPU to the finned metal. Larger fans are quieter too. If all else fails water cool the thing which is what the serious overclockers do.
The way to cool it is use a larger heatsink designed to match the CPU surface and use the right compound to make the best thermal joint.
-- Regards, Martin Brown
Since the heatpipes of each would be very close, the length of normal steel would be minimal.
I don't give a f*ck. And that does explain why the monitor jumps a bit. There are 5 such open cased machines there. I wonder if that's why my neighbour has installed some kind of WiFi repeater in his garden :-) Pissed him off without even trying!
But the interface between the CPU and the block would be the same size - the area of the CPU.
Expensive, hassle, leakages....
And serious overclockers use liquid nitrogen, or submerse the whole thing in oil!
I just replaced the fan with a faster one. Lost 20C. I'd forgotten how shit some fans are. 1100rpm to 4000rpm!
A highly faulty analysis.
People often think the best match for power is equal impedance, but that is not the case when the impedance of the load is fixed. In that case the lo west possible impedance in the supply provides for the optimum power transf er. That's why power supplies are designed with very low output impedances . Same thing here, only the guy is trying to optimize his costs, rather th an ultimate effectiveness of the cooling.
I have no idea what his heat sinks look like or how he plans to attach them , but adding a second heat sink will most likely improve his cooling. The only question is by how much. That can't be answered without more informat ion. He talks about "a" heat pipe being near the top of the heat sink, but any one heat pipe has limited heat capacity, so still insufficient info.
-- Rick C. -- Get 1,000 miles of free Supercharging -- Tesla referral code - https://ts.la/richard11209
WTF are you talking about "normal steel"??? Each heat pipe can only carry a small amount of heat, that's why they use many. Otherwise they would just use one pipe snaked along the fins.
You are starting to sound like a dick who used to post here under another name that I can't recall. What was it? You used to blow up stuff and get mad at the people who made it.
Yes, you are very definitely not understanding what is going on. If the interface to the CPU was the limiting factor in heat conduction, then you would not get better performance by stacking your heat sinks either.
So you just want to do something lame and pathetic?
Yeah, it's not uncommon for people to rush to a solution before they have all the facts. Still wanting to stack heat sinks?
-- Rick C. -+ Get 1,000 miles of free Supercharging -+ Tesla referral code - https://ts.la/richard11209
I mean metal that isn't a heatpipe.
I assumed snaking would be harder to make. Anyway since the original heatpipes are still almost as hot at the top as the bottom, I'm sure they could carry more if the top of them was cooled by another heatsink.
I set fire to a strimmer once. I haven't blown much up, unless you call smashing the spark plugs in a Renault engine "blowing up". All I did as overrev it, assuming that all modern cars had a rev limiter. but then the French are a bit lackadaisical.
Bullshit. It's not as simple as traffic on a road, where one junction is the bottleneck and no changes to surrounding roads makes that junction any faster. If the interface to the CPU is limiting heat transfer, and say producing a temperature difference of 20C between the CPU and heatsink block, and then you make the heatsink colder by a bigger fan or a bigger heatsink, you could increase that 20C difference, causing more heat to flow through your so-called "bottleneck". Think of it like a garden hose, the width of the hose is limiting the water transfer. But if you increase the pressure, more gets through.
I want to make it run cooler without expense or time.
I'll correct that for you, "it's common for people...." You do like to do things the longwinded way don't you? Stacking the heatsink was the easiest way to fix the problem.
It is in stereos.
Ah so now you admit my idea was sensible.
There's 4 running from the block through the fins to the top.
The top is almost as hot as the bottom, the pipes are not a limiting factor.
te:
nd
steel would be minimal.
se many. Otherwise they would just use one pipe snaked along the fins.
tpipes are still almost as hot at the top as the bottom, I'm sure they coul d carry more if the top of them was cooled by another heatsink.
Did you measure? I'm sure stacking heat sinks will improve the heat flow. The issue is how much. I expect it will be a lot less than the original h eat sink.
e in
s on
spare
nto.
nGHz.
t. There are 5 such open cased machines there. I wonder if that's why my neighbour has installed some kind of WiFi repeater in his garden :-) Pisse d him off without even trying!
er name that I can't recall. What was it? You used to blow up stuff and g et mad at the people who made it.
smashing the spark plugs in a Renault engine "blowing up". All I did as ov errev it, assuming that all modern cars had a rev limiter. but then the Fr ench are a bit lackadaisical.
Maybe you aren't guy I'm thinking about. He would do goofy stuff and end u p ruining computers and components.
heat
om
- the area of the CPU.
e interface to the CPU was the limiting factor in heat conduction, then you would not get better performance by stacking your heat sinks either.
the bottleneck and no changes to surrounding roads makes that junction any faster. If the interface to the CPU is limiting heat transfer, and say pr oducing a temperature difference of 20C between the CPU and heatsink block, and then you make the heatsink colder by a bigger fan or a bigger heatsink , you could increase that 20C difference, causing more heat to flow through your so-called "bottleneck". Think of it like a garden hose, the width of the hose is limiting the water transfer. But if you increase the pressure , more gets through.
That's true, but you are the one talking about the limitation imposed by th e area of contact to the CPU.
.ing in oil!
How much expense? Everything has expense and time.
tain
f the
Uow shit some fans are. 1100rpm to 4000rpm!
ve all the facts. Still wanting to stack heat sinks?
o things the longwinded way don't you? Stacking the heatsink was the easie st way to fix the problem.
No need to correct anything, it was perfectly correct the first time and yo u now have altered the meaning. So what name did you used to post under? You didn't answer that.
Stacking heat sinks is not likely to "fix" anything. It may gain you some minimal reduction of temperature at the CPU but I expect "minimal" to be th e important word there.
In the end you have found the real problem that needed to be "fixed", a def ective fan. Since the original heat sink was not working correctly, stacki ng another heat sink very possibly would have improved the heat flow enough to be useful and you would have declared it "fixed" even though you had no t found the real source of trouble.
It doesn't take a PhD to realize the stacking thing was a bad idea from the start.
-- Rick C. +- Get 1,000 miles of free Supercharging +- Tesla referral code - https://ts.la/richard11209
e:
t is not the case when the impedance of the load is fixed.
That shows you didn't understand anything I wrote.
he optimum power transfer. That's why power supplies are designed with ver y low output impedances. Same thing here, only the guy is trying to optimi ze his costs, rather than ultimate effectiveness of the cooling.
them, but adding a second heat sink will most likely improve his cooling. The only question is by how much.
No, again, you don't understand what I wrote. I can make a car go faster f rom a start by dumping the clutch. Doesn't mean it's a good idea or "sensi ble". Read what I wrote... carefully.
at pipe being near the top of the heat sink,
info.
or.
Not in your case where the fan was not working correctly.
-- Rick C. ++ Get 1,000 miles of free Supercharging ++ Tesla referral code - https://ts.la/richard11209
te:
second
mal steel would be minimal.
ey use many. Otherwise they would just use one pipe snaked along the fi= ns.
heatpipes are still almost as hot at the top as the bottom, I'm sure th= ey could carry more if the top of them was cooled by another heatsink.
low. The issue is how much. I expect it will be a lot less than the or= iginal heat sink.
I did measure, with the very accurate sensor built into my fingertip. H= ow long can you keep your finger on the surface before saying ouch, is p= retty accurate to compare one thing to another. Plumbers actually use i= t to make sure a central heating system is heating the radiators to a se= nsible temperature.
state in
sits on
of spare
rd into.
than
to GHz.
a bit. There are 5 such open cased machines there. I wonder if that's = why my neighbour has installed some kind of WiFi repeater in his garden = :-) Pissed him off without even trying!
nother name that I can't recall. What was it? You used to blow up stuf= f and get mad at the people who made it.
all smashing the spark plugs in a Renault engine "blowing up". All I di= d as overrev it, assuming that all modern cars had a rev limiter. but t= hen the French are a bit lackadaisical.
end up ruining computers and components.
I am goofy, but not with computers. I usually break cars. Ever seen a = tractor with the front half on the other side of the road, and the back = half tipped over with the driver yelling abuse?
the heat
d.
t from
size - the area of the CPU.
f the interface to the CPU was the limiting factor in heat conduction, t= hen you would not get better performance by stacking your heat sinks eit= her.
n is the bottleneck and no changes to surrounding roads makes that junct= ion any faster. If the interface to the CPU is limiting heat transfer, = and say producing a temperature difference of 20C between the CPU and he= atsink block, and then you make the heatsink colder by a bigger fan or a= bigger heatsink, you could increase that 20C difference, causing more h= eat to flow through your so-called "bottleneck". Think of it like a gar= den hose, the width of the hose is limiting the water transfer. But if = you increase the pressure, more gets through.
by the area of contact to the CPU.
The "limitation" I mentioned was the size of the CPU area. So you canno= t increase that without changing the CPU.
s do.
e thing in oil!
It's a =A37 CPU. A =A350 cooler is absurd.
certain
om of the
e CPU
t.
en how shit some fans are. 1100rpm to 4000rpm!
y have all the facts. Still wanting to stack heat sinks?
to do things the longwinded way don't you? Stacking the heatsink was th= e easiest way to fix the problem.
nd you now have altered the meaning.
No. It meant precisely what you did. I removed two negatives. As any = mathematician will tell you, two negatives make a positive. Eg., "I don= 't doubt it" means "I think so".
Several. Offhand I can think of Lieutenant Scott and Uncle Peter.
some minimal reduction of temperature at the CPU but I expect "minimal" = to be the important word there.
a defective fan.
Not defective per se, just shit. Strangely the same model of fan and he= atsink cools the other three CPUs ok. Either one CPU runs hotter as it'= s buggered, or the motherboard voltage regulation for it is off, or that= area has warmer air in it.
er heat sink very possibly would have improved the heat flow enough to b= e useful and you would have declared it "fixed" even though you had not = found the real source of trouble.
m the start.
No, since the fan was insufficient, stacking two together would have wor= ked well, doubling the number of fans (therefore the airflow), and doubl= ing the surface area of fins to transfer heat to the air.
I understood it perfectly. I was pointing out that you were not correct in all cases. In a stereo the impedance of the load is fixed, the speaker doesn't change.
Dumping the clutch causes damage, my idea would not.
e:
econd
al steel would be minimal.
y use many. Otherwise they would just use one pipe snaked along the fins.
heatpipes are still almost as hot at the top as the bottom, I'm sure they c ould carry more if the top of them was cooled by another heatsink.
ow. The issue is how much. I expect it will be a lot less than the origin al heat sink.
w long can you keep your finger on the surface before saying ouch, is prett y accurate to compare one thing to another. Plumbers actually use it to ma ke sure a central heating system is heating the radiators to a sensible tem perature.
And yet you failed to recognize the lack of heat flow because of the bad fa n.
tate in
sits on
of spare
d into.
than
to GHz.
bit. There are 5 such open cased machines there. I wonder if that's why my neighbour has installed some kind of WiFi repeater in his garden :-) Pi ssed him off without even trying!
other name that I can't recall. What was it? You used to blow up stuff an d get mad at the people who made it.
ll smashing the spark plugs in a Renault engine "blowing up". All I did as overrev it, assuming that all modern cars had a rev limiter. but then the French are a bit lackadaisical.
nd up ruining computers and components.
ractor with the front half on the other side of the road, and the back half tipped over with the driver yelling abuse?
he heat
.from
ize - the area of the CPU.
the interface to the CPU was the limiting factor in heat conduction, then you would not get better performance by stacking your heat sinks either.
is the bottleneck and no changes to surrounding roads makes that junction any faster. If the interface to the CPU is limiting heat transfer, and say producing a temperature difference of 20C between the CPU and heatsink blo ck, and then you make the heatsink colder by a bigger fan or a bigger heats ink, you could increase that 20C difference, causing more heat to flow thro ugh your so-called "bottleneck". Think of it like a garden hose, the width of the hose is limiting the water transfer. But if you increase the press ure, more gets through.
y the area of contact to the CPU.
increase that without changing the CPU.
Which is nothing anyone was talking about other than you. Like most ration al people it was pointed out that the obvious solution was to use a better heat sink rather than trying to jury rig something. You failed to mention your financial constraints initially.
do.
thing in oil!
Actually it's not. If that is the best way to repair something, then the c omparison is the value of the repaired item vs. the value of the broken ite m. You didn't discuss any of this initially.
certain
m of the
CPU
.n how shit some fans are. 1100rpm to 4000rpm!
have all the facts. Still wanting to stack heat sinks?
o do things the longwinded way don't you? Stacking the heatsink was the ea siest way to fix the problem.
d you now have altered the meaning.
athematician will tell you, two negatives make a positive. Eg., "I don't d oubt it" means "I think so".
Not really. You altered the meaning because you are limiting your thinking to a binary choice. It's not binary.
Ok, then you aren't the guy I was thinking of.
ome minimal reduction of temperature at the CPU but I expect "minimal" to b e the important word there.
defective fan.
tsink cools the other three CPUs ok. Either one CPU runs hotter as it's bu ggered, or the motherboard voltage regulation for it is off, or that area h as warmer air in it.
Yes, defective. You said it ran slower than the others, so not working cor rectly. A fan is a very simple device. Hard to say it's not working right without being "defective".
r heat sink very possibly would have improved the heat flow enough to be us eful and you would have declared it "fixed" even though you had not found t he real source of trouble.
the start.
ed well, doubling the number of fans (therefore the airflow), and doubling the surface area of fins to transfer heat to the air.
Your jury rig would have partially compensated for the broken fan, but the fact remains that you did not pay attention to what was going on and diagno se the failed fan. So the stacked heat sink would have been doubly bad, st ill not working like it should and covering up the actual failure.
-- Rick C. --- Get 1,000 miles of free Supercharging --- Tesla referral code - https://ts.la/richard11209
rote:
ond
that is not the case when the impedance of the load is fixed.
in all cases. In a stereo the impedance of the load is fixed, the speaker doesn't change.
If you fix the load impedance, what do you change? If you can't change any thing there is nothing to compare. So again, you fail to understand what I wrote.
r the optimum power transfer. That's why power supplies are designed with very low output impedances. Same thing here, only the guy is trying to opt imize his costs, rather than ultimate effectiveness of the cooling.
ch them, but adding a second heat sink will most likely improve his cooling . The only question is by how much.
er from a start by dumping the clutch. Doesn't mean it's a good idea or "s ensible". Read what I wrote... carefully.
That doesn't equate to sensible. It was a lame idea that you came up with because of a failure to diagnose the real problem, lack of air movement. C learly the idea of fixing a lame fan by adding another heat sink is a lame idea.
-- Rick C. --+ Get 1,000 miles of free Supercharging --+ Tesla referral code - https://ts.la/richard11209
You compare different source impedances duh. That's the only variable left.
No, because it would have worked, and would have been quieter than a powerful fan.
:
second
ut that is not the case when the impedance of the load is fixed.
ct in all cases. In a stereo the impedance of the load is fixed, the speak er doesn't change.
anything there is nothing to compare. So again, you fail to understand wh at I wrote.
ft.
So what happens as you lower the source impedance? At what point do you ge t the most power into the load?
for the optimum power transfer. That's why power supplies are designed wi th very low output impedances. Same thing here, only the guy is trying to optimize his costs, rather than ultimate effectiveness of the cooling.
ttach them, but adding a second heat sink will most likely improve his cool ing. The only question is by how much.
aster from a start by dumping the clutch. Doesn't mean it's a good idea or "sensible". Read what I wrote... carefully.
ith because of a failure to diagnose the real problem, lack of air movement . Clearly the idea of fixing a lame fan by adding another heat sink is a l ame idea.
rful fan.
1) You don't know if it would have worked because you have no idea how much heat would have found it's way into the second heat sink. 2) You said "quiet" didn't matter because the rig is in the garage.I don't know why you keep going on about this. You eventually diagnosed th e real problem and got a fix. The idea of stacking heat sinks is not very practical and may or may not have "worked" since there is no clear definiti on of "worked".
-- Rick C. -+- Get 1,000 miles of free Supercharging -+- Tesla referral code - https://ts.la/richard11209
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