Dumb question?

[Junkkyy]

Ok, got my shiny new XP 1.67Ghz system, works fine except for the heat. It idles at 56C and gets up to 63C under load. I have a decent heatsink/fan, but the one thing that seems strange to me is that the fan blows the air *onto* the heatsink. It seems like the best design would blow air out away from the heatsink, and the cooler air would get sucked back through right? What do your systems do? It doesn't make sense to me, but the fan is facing the right way- it can only be mounted face up. Maybe the wires were crossed and it rotates in the wrong way? If I switched red & black, would that reverse the fan direction? Please let me know which way your heatsink fans blow air. Thanks.

Never underestimate the bandwidth of a station wagon full of tapes hurtling down the highway

 

[garett]

im sure someone will come along and write a really long explanation of the physics of heatsinks, so ill just be short and say that the fan is facing the right direction.

however there could be serveral reasons for too much heat. a recent thread depicted that someone was having heating problems and all they had to do was remount the heatsink(wasnt on very good)

did you use thermal paste?

 

[Junkkyy]

Yeah I went ahead and remounted it using AS3- minor improvemnt, but I still top out around 62C. Granted, it's not a great heatsink (thermaltake 5), and its one of the hottest processors on the block (XP 2000), but still, doesn't seem like it should be that hot. Also, any attempts at overclocking even slightly fail miserably. Guess I need a Thoroughbred?

Oh and by now you're probably guessing I don't know how to use thermal paste, or that the heatsink isn't fastened well, but it's neither of those, trust me

Never underestimate the bandwidth of a station wagon full of tapes hurtling down the highway

 

[kamo]

That's not even close to hot
be happy, or uderclock the stove and then be happy.
Changing the wires reverse the rotate direction (don't rember colors )

<font color=green> The second time is always better than the first </font color=green>

 

[ritesh_laud]

It seems like the best design would blow air out away from the heatsink, and the cooler air would get sucked back through right?

I've seen both designs. Personally all HSFs I've used have blown air out from the heatsink and I think that's more common, but it's really not a big deal. As an engineer I can sort of explain the argument behind each design:

<font color=orange>Blowing air *out of* heatsink</font color=orange>
Produces a smoother and more "laminar" flow than the other design because you're blowing straight out into open air (nothing in the way to disrupt the flow). Hence less pressure drop through system. Hence greater velocity and volumetric flow of air over heatsink fins. Hence faster removal of heat.

<font color=orange>Blowing air *onto* heatsink</font color=orange>
Produces more "turbulent" flow because the heatsink is sitting right in the way which disrupts the flow. More pressure drop and hence lower velocity, BUT turbulence improves heat transfer. Also, this design will probably cause the moving air to touch more of the heatsink (and hence remove more heat), due to the chaos and turbulence. The other design is more likely to find "pathways" through the heatsink that present the least resistance, which may cause parts of the heatsink to have hardly any air flowing over them.

The pros and cons of each design probably roughly balance out and in the end it doesn't make much of a difference.

If I switched red & black, would that reverse the fan direction?

Maybe, depends on the motor. Some motors can be reversed by switching the current around, others can't.

Anyway, run Toast for ten minutes and if you don't lock up you're fine. Instabilities generally arise with CPU temps around 60°C, but I would never trust the CPU temp reading on an Athlon system since the vast majority of Athlon mobos don't use the core diode for temps. They use an inaccurate reading off the socket, which can easily be 20°C or more off the core reading when temps are rising rapidly like in Toast. So the only true guage of your CPU temp is whether or not you're locking up.

Ritesh

 

[garett]

see, i knew someone would come around and explain it all

 

[blue_heart]

your problem is in the heatsink you are using, the model you chose supports XP1700+ as a maximum model, therefore you need thermaltake 6 but i prefer thermaltake Volcano 7+ so you will get the best results and your temp with AS3 should be less 40c (in case you used 2 case fan you will be under 40c)

there is even newer volcano models but haven't check for their reviews yet

<A HREF="http://www.thermaltake.com/" target="_new">check thermaltake site for more etails</A>

<A HREF="http://www.amd.com/us-en/Processors/TechnicalResources/0,,30_182_869_4348^4356,00.html" target="_new">visit AMD site</A> to get more info about heatsink types you need to use with your cpu

wish if there was UnDo in the life

 

[MeTaLrOcKeR]

Gte a new cooler...the Thermaltake Volcano 5 is NOT rated for an XP 2000+, the Thermaltake Volcano 7 should be good...im running my XP 1600+ @ 1.66GHz witht he Volcano 7 and i top out at 41 Celcious ina room that about 26 degrees celcious....and its just got generic Thermal paste on there......so its decent to me...stock voltage too.....

<A HREF="http://www.anandtech.com/mysystemrig.html?id=13597" target="_new">-MeTaL RoCkEr</A>

 

[bront]

The idea of blowing air onto the HS is to push cooler air into the HS, and the warmer air is pushed away. There are 2-3 HSF that work the other way, but even those, when tested, didn't do any better or worse when the fan was reversed.

English is phun.

 

[Junkkyy]

Ah ok, those bastards gave me a heatsink that isn't even rated for my CPU?!!

All is good though, Thermalright Sk6 is in the mail.

Also, I reversed the fan direction and that gave me a decent little drop in temp (62->58) under stress. I still say that having the fan blow towards the heatsink is just sick and wrong

Never underestimate the bandwidth of a station wagon full of tapes hurtling down the highway

 

[Crashman]

Let's see, the delema, do we want to pull HOT air from close to the motherboard through the heatsink, or do we want to blow COOLER air from 2 inches away from the motherboard INTO the heatsink. If that's not a good enough reason, how about this-fans pull from the side but push to the center. If that's not a good enough reason, how about this-when you pull air, you make it less dense, when you push air, you make it more dense. The higher the density of air, the better it works for cooling. Liquid air would be almost perfect!

<font color=blue>At least half of all problems are caused by an insufficient power supply!</font color=blue>

 

[ritesh_laud]

The idea of blowing air onto the HS is to push cooler air into the HS, and the warmer air is pushed away.

Huh? Regardless of which way the fan blows, the source air is roughly at case temperature. If the fan blows out from the HS, cool air still replaces the air that's sucked out. The only difference is the source air is two inches lower and off to the side of the HS. Still cool though, because it hasn't touched the HS yet.

Ritesh

<P ID="edit"><FONT SIZE=-1><EM>Edited by ritesh_laud on 07/17/02 01:11 PM.</EM></FONT></P>

 

[slvr_phoenix]

Liquid air would be almost perfect!

Yet somehow, I think using LOX would be a bad idea...

On a more serious note though, I wonder how long it will be before good quality closed-system watercooler becomes a standard part of PC cases. Could you imagine it being standard to have some nice copper piping with a closed water well built into the case. Just clamp the water block onto the CPU and violla. Low noise, low maintanance, high cooling. Who could ask for more?

<A HREF="http://www.nuklearpower.com/comic/171.htm" target="_new">The corpse you find may be your own.</A> - Black Mage

 

[Crashman]

Actually air is 78% nitrogen. But water cooling is second to heat pipes as being an ideal cooling method, and heat pipes are cheaper and far more reliable.

<font color=blue>At least half of all problems are caused by an insufficient power supply!</font color=blue>