Plug up your nose, a probable dive into Pelt cooling!

[XeroHouR]

Ok I'm beginning to cave. I just need to learn a few things first. I've read about 15 articles online about this and it all looks like stuff I can handle. I'm pretty sure that given I have enough room below my card I'm going to give her a shot! I just have a few questions for the pros here!

The project is to pelt cool an FX5900 with a dangerden maze4 + peltkit

1.) I have a 430watt truepower with only 1 hard drive and 1 cdrom drive, and 2 fans. Would the pelt included with the kit put me out of my range of power? I'm not sure what all the drops are, but if anyone could lemme know that'd help me decide!

2.) I have a little packet of dielectric grease and a big tube of Dow Corning conformal coating. From what I've seen online undertakers(=-O) of this task have used the dow coating on the pcb and then the dielectric around the silicone and the pelt on the gaskets to seal it up. Why not use the conformal coating on all of it? What exactly is the little pack of dielectric for?

3.) Can anyone report thier increase in temp in THIER pelt/water cooled system, from the GPU not the CPU. I've read 5-9oC which I suppose I can live with if I can see some returns on my cards speeds.

4.) Anyone think my single rad with 2 fans push pull won't dissapate the heat?


The reason I'm doing this mostly is because my cpu and my NB must be warming my water up because when I play painkiller or run benchmarks I can alt+tab and go to the temp sensor and it pushes on high 70's. This inturn leads to crashes and thermal throttling(stupid thing goes from 485 to 325 on the core becuase it thinks its too hot!). So I figured I've had this pelt kit laying around I should try to use it to lower my temps in the shadow of the Doom III release.

thanks in advance!

[cadaveca]

i'm by no means even close to an expert, but maybe the bump will help...
conformal coating is non.conductive sealer
maybe di-electric grease is a as well, but seals against corrosion as well...so on metal stuff you may want to use dielectric to prevent any consnesation that might posiibly appear from affecting it.
as well i think that conformal coating is a insulator(heat). i don't think you are supposed to glop on dielectric like conformal...


dielectric for the socket and conformal grease for other areas??

[XeroHouR]

well dielectric means it basically doesn't conduct(or has very low conductivity, siemens). the conformal coating is too though, i still dont know why they dont use the conformal on the neoprene.... anyone?

[Gizmo]

I would use the dielectric grease to seal the cpu pins in the socket. Basically, take that stuff and smear it all over your cpu socket, working into the cups of the socket. You do that to prevent condensation buildup in the CPU pins. Then use the conformal coating for everything else.

[cadaveca]

how long will these compounds be good for?
i've never had anything -0 except a 686...and i dunno what sort of grease we used...had a blue tinge to it.

[Gizmo]

I would think they would be good for at least as long as the CPU is good for. LOL

[Aedan]

As I don't know much about the DD kits I'm assuming that the peltier would be the 226W one that DD do? If so, when it's running flat out at 15V, it needs 365W of power on it's own. If you're running it on 12V, it will need about 227W of power on it's own, assuming the TEC's response is linear.

The Antec 430W Truepower PSU can supply 240W of 12V (20A). If the TEC is taking 227W (~18.9A) of that, the rest of the machine is left with 13W to operate on! That's not going to be enough.

As far as the conformal coating goes, depending on the solvant used, it may well dissolve/damage the neoprene. Conformal coating is good at water resistance, but not good at thermal insulation. Neoprene is pretty good at thermal insulation.

What temperature is your coolant and room? You can do a back-of-an-envelope calcuation to see the thermal resistance of your system, and then do a recalculation of approximate temperatures when you add another 400W worth of heat to it.

At the moment, it would appear that the answer is less than clear cut as to how effective it would be.

[XeroHouR]

umm guys lol...read the first post

[XeroHouR]

Originally Posted by XeroHouR

The project is to pelt cool an FX5900 with a dangerden maze4 + peltkit

Now that we're back on topic lets try again

I became confused when Gizmo randomly started talking about CPU pins and the dielectric grease. Man that old age thing keeps coming up in my posts where you reply :-D. So in the event of no pins for the dielectric grease, where else would I use it?

And to my knowledge its the pelt thats somewhere around 80W(ballpark guess)

[Aedan]

Do you know how much heat the FX5900 kicks out? If it's close to the total heat the peltier can pump, then don't even try! There needs to be a good bit of overhead between the heat the FX5900 kicks out and the heat the peltier can pump.

In your case, the grease might not be of any use. If you take the FX5900 down below ambient temperature, then you might need insulation to maximise returns from the peltier.

[Gizmo]

Originally Posted by XeroHouR

I became confused when Gizmo randomly started talking about CPU pins and the dielectric grease.

Sorry about that. Occasionally my mind leaves my body unattended at the keyboard.

[Aedan]

Originally Posted by gizmo

Occasionally my mind leaves my body unattended at the keyboard.

I have a friend who has been known to fall asleep whilst typing emails. Unfortunately, they continue typing their email whilst asleep!

[cadaveca]

Occasionally?lol

j/k

the best i could find is that your dielectric grease is of no use to the vid card...dielectric will allow touching connectors to connect, but it seems as tho conformal does not, so would explain why dielectric is used on the socket and conformal elsewhere.
i'm trying to locate the name of the blue goop i used way back...non-conductive gelatin i beleive, but i have yet to find the can in my storage room. the big thing about it was it is NATURAL, so no solvents that may possibly deteriorate the pcb over time, which i guess is an issue with conformal. remember that most guys going sub zero are not doing it forever, or have access to tons of parts for very little or free.

[Aedan]

Conformal coating is often used on PCBs to provide a level of protection. This is especially so when high voltages are used, as through hole soldering tends to leave places where high tension can stream off easily. That means sparks! Putting a layer of conformal coating over it helps to prevent this.

I wish I had access to lots of parts for nearly nothing/free!

[XeroHouR]

the amount the pelt can pump is its rating I assume.

I suppose now is as good time as any to ask, why does a 430W powersupply only put out 230W? Why is it less?

[cadaveca]

Originally Posted by Áedán

Conformal coating is often used on PCBs to provide a level of protection. This is especially so when high voltages are used, as through hole soldering tends to leave places where high tension can stream off easily. That means sparks! Putting a layer of conformal coating over it helps to prevent this.

I wish I had access to lots of parts for nearly nothing/free!

do ya go sub zero?
do you use conformal yourself, or do you have a neoprene gasket?

[Aedan]

Ahh. Yes.

Well, the power supply puts out some power at 12V, some at 5V and some at 3.3V. There's a couple of negative lines, but they're practically unused now.

The 430W PSU can put out on each individual line:
230W on the 12V line.
180W on the 5V line.
92.4W on the 3.3V line.

That's a total of 502.4W! However, other aspects of the PSU can only cope with a total sum of 410W across those three lines. The extra 20W come from the standby power and the two negative voltages.

So, combining all of the figures gets you a total of 430W. Antec are quite good in the fact that they ensure that their figures are realistic. Other manufacturers just sum up the figures and give you a vastly overrated number at the end, rather than what the PSU can actually supply.

[Aedan]

Originally Posted by cadaveca

do ya go sub zero?
do you use conformal yourself, or do you have a neoprene gasket?

Currently I don't go sub zero for a variety of reasons. Conformal coating I only use on high tension(voltage) circuits, as generally the designs can't afford power leaking away from soldered junctions.

Neoprene is known for it's heat insulation properties, which is something you want for sub zero operation. That helps to prevent heat leaking in from the environment.

[Kaitain]

Originally Posted by cadaveca

do ya go sub zero?
do you use conformal yourself, or do you have a neoprene gasket?

Do you?

[cadaveca]

hell no!
i have the fridge in storage to set up a 2-phase phase change setup, but dude who has the cfc handling liscense does not have the time to do the work for me yet.
closest i've gone is dry ice.
that was a pc that went directly to the dumpster after we we done that day.