what heatsink - Page 3

26th February 2004, 17:22

no, I forgot about that.

my 2nd machine is home again, I'll start testing.... er....

how about now

26th February 2004, 18:11

ok, here's the setup
Koolance Case, 350W Enermax PSU, dual fans at low speed

ECS K7S5A, 2000+ Tbred A, a stock 2500+ heatsink (alu-cu), a v7+ heatsink and the 2500+ 60mm fan. I'll also do some testing with a 60-80mm fan adapter and a silent 80mm sleeve bearing fan

26th February 2004, 19:28

alu/cu, 60mm fan, 12v: CPU 43°, case 32°, ambient 25.5°

jmke · 26th February 2004, 20:04

and the copper one?

26th February 2004, 20:07

heheheheh. I have my own way to test heatsinks

same setup, fan on 7volt: CPU 51, case 31~32

26th February 2004, 22:18

fan at 5v: CPU 62, case 31

if my 60-80mm fan adapter gets here by the weekend I'll wait to test with a 80mm fan, if not I'll test the V7+

27th February 2004, 10:44

v7+ heatsink: CPU 49, case 33

27th February 2004, 13:39

V7+, fan at 7v: 58°/31°

27th February 2004, 14:09

Quote:

Originally posted by 8-ball
When will people learn that HSF manufacturers only use aluminium because it is:

cheaper
lighter
cheaper
easier to manufacturer
cheaper

and did I mention cheaper.

I will concede that aluminium DOES radiate thermal energy better than copper. However, raidation is simply not a significant mode of heat dissipation unless you are cooling something in a vacuum. It also needs to be significantly hotter than the surroundings to get a reasonable amount of heat dissipation.

As for convection.

Convective heat transfer, the process by which thermal energy is transferred from a solid into a moving body of fluid, such as water in your water block, or air flowing through a rad, is INDEPENDENT of the material of which the rad/block is manufactured.

The only bearing the material has on the heat transfer is getting the thermal energy to the surface. Once it is at the surface, it may as well be glass for all I care. The only thing which determines how well the thermal energy is dissipated in to the air flow, is the physical properties of the liquid/gas, the flow regime, and the geometry of the transferring surface.

8-ball

Quote:

Originally posted by 8-ball
Aluminium IS a better radiator, in that its radiating properties are closer to that of a black body than copper.

However, as I said, radiation simply doesn't figure significantly enough for using aluminium to perform better than copper due to the performance hit associated with the conduction of thermal energy to the dissipating surface.

Just about the only scenario where aluminium's better radiating (and let me point out, that it isn't that much better) properties justify it's use are in space, where ALL thermal energy must be dissipated by radiation due to the vacuum.

As long as there is some medium to carry the heat away by convective heat transfer, then radiation properties are pretty irrelevent.

8-ball

Quote:

Originally posted by 8-ball
As i understand it, the myth that aluminium is a better radiator, (and a common myth) is down to the radiative properties of the materials. It is true that aluminium is a better radiator, but radiation doesn't playa big enough role for this fact to outweigh it's much poorer conductivity.

As I alos said, and you correctly backed up, cost is the predominant factor in using aluminium over copper for thermal management applications, and maybe weight.

8-ball

http://www.xtremesystems.org/forums/...threadid=30286

jmke · 27th February 2004, 14:30

Quote:

Originally posted by TeuS
V7+, fan at 7v: 58°/31°

ineens 7°C warmer als voor den edit?

26th February 2004, 20:04	#24
jmke Madshrimp Join Date: May 2002 Location: 7090/Belgium Posts: 78,417	and the copper one? __________________

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26th February 2004, 17:22	#21
TeuS Posts: n/a	no, I forgot about that. my 2nd machine is home again, I'll start testing.... er.... how about now

26th February 2004, 18:11	#22
TeuS Posts: n/a	ok, here's the setup Koolance Case, 350W Enermax PSU, dual fans at low speed ECS K7S5A, 2000+ Tbred A, a stock 2500+ heatsink (alu-cu), a v7+ heatsink and the 2500+ 60mm fan. I'll also do some testing with a 60-80mm fan adapter and a silent 80mm sleeve bearing fan

26th February 2004, 19:28	#23
TeuS Posts: n/a	alu/cu, 60mm fan, 12v: CPU 43°, case 32°, ambient 25.5°

26th February 2004, 20:07	#25
TeuS Posts: n/a	heheheheh. I have my own way to test heatsinks same setup, fan on 7volt: CPU 51, case 31~32

26th February 2004, 22:18	#26
TeuS Posts: n/a	fan at 5v: CPU 62, case 31 if my 60-80mm fan adapter gets here by the weekend I'll wait to test with a 80mm fan, if not I'll test the V7+

27th February 2004, 10:44	#27
TeuS Posts: n/a	v7+ heatsink: CPU 49, case 33

27th February 2004, 13:39	#28
TeuS Posts: n/a	V7+, fan at 7v: 58°/31°