New to cooling question...

[henryscat]

Im new to cooling, but I understand the physics. Currently I have an AMD k6-2/350 with a standard heat sink and a big fan, over clocked to 400mhz (100 fsb x 4). If I go to 450 the motherboard wont initialise at all. Why is this? I had expected to run up until there was some real processor activity before the heat crashed it, at high speeds is it worth upping the core voltage ?

[train22]

welcome to da forums...
If you are bellow 40C @ Idle temps you can punch the Vcore up a knotch but be carefull when burning, make sure you mointor your temps and have it shut down if it passes 55. What is your Vcore right now?

I think you'll need to add a few more fans...

[henryscat]

V-core at the moment 2.2v, I have one fan (28cfm I think) standard position and one fan (about 5 cfm!) from the side, airflo along the fins. I have no temp monitoring on the mobo but I going to stick a thermister in and read it from a serial port with a little app in C this week if I get round to it. Also I am machining a water cooled heatsink which I am going to try and refrigerate at some point. Same question though, why wouldn't the mobo initialise at all at 450 ?

[train22]

It is because of the cpu not the mobo. The cpu can only be overclocked so much and if you reach that sweetspot the only thing you can do is feed in some Vcore power or downclock it to the last stable state. I don't recommend overclocking at all until you get your therm under that cpu.

[henryscat]

ok, cheers. I am just looking at peltier coolers from Maplin electronics (uk), they are rated as maximum hot-side temp 80degC, does this refer to the max temp without cooling, or the max temp with the peltier running. A peltier is just a heat pump, right? so you use it instead of a block heatsink and add fins or water cooling to the hot side...?

[train22]

Yes that's basically how you use it, although most people use it with a waterblock. 80C is the heat produced with the X amount of watts. Pelts, also known as TECs, used to be somewhat useful but nowadays they are gonna help a whole lot, it's like "middle man market-man" They use so much power yet they will only help on 1C to 2C. The cold side gets heated up quickly and nothing can cool it down the hot side enough to let the cold side stay cold, not to mention the fact the cpu die is also heating up the cold side. I wouldn't jump at the idea quite yet.

incase I wasn't clear enough, 80C is what the pelt produces alone, when it's not touching anything.

[henryscat]

so, in other words, I would get better cooling by adding a water block and refrigerating the water than I would with a water-cooled peltier then? Basically to cool well you need the largest heat differential possible, so the cooler I can get my heat transfer medium the better. Is a peltier just not worth having over an aluminium heatsink, assuming the transfer medium (water or air) is the same?

[train22]

yes a pelt is not as useful as many think it to be...

If you consider air-cooling you'll have to find a good HSF and make sure case cooling is good too! The SK6 is a good HS but a little loud with the delta, if that's an issue try a swify.

If you are going to go for the water solutions (Recommended) I would use a MazeII Waterblock and you can look around for the radiator, tubing and pump. This will be a little harder than air-cooling but if done right will be much closer to ambient temps and low noise. Here is a koolance model which I highly suggest going by, it's a nice design, you may not wish to use dual pumps simply for the cash but the arrangement is good:

http://koolance.com/products/pc2/PC2_SideCircle1.jpg
Very well organized.

http://koolance.com/products/pc2/top/AirFlow_Diagram1.gif
Radiator is well designed, long and thin so the air doesn't warm up quickly when cooling the water, at the top so not to bring heat into the case. (Still does but less than if you were to put the radiator on the bottom)

http://koolance.com/products/pc2/top/Radiator1_large.jpg
Here's the radiator again.

http://www.koolance.com/products/pc2/reservoir/reservoir1_large.jpg
-The reservoir, which includes the 2 pumps, one sucking, one blowing
-Although you will be fine with 1 strong one. The only big advantage is the backup feature; if 1 pump dies the other will slowly show an increase in temps rather than a more drastic one.

http://www.koolance.com/products/pc2/cpu/CPU1_large.jpg
This is how their waterblock looks although I would suggest using the DangerDen MazeII waterblock if you were to design your own custom water-cooled rig.

These are the basic features of a water rig, you can add vid coolers etc, but I wouldn’t worry about that now, first start with these.

Good luck, hope this helps.

[William]

Peltiers yield much better results than chilled water, as they cool better than chilled water. On a k6-2 you can aircool a pelt as they don't produce a ton of heat so you can get away with a good heatsink(Alpha 6035 should do well). You have to water cool a pelt for a duron/tbird just because of the heat a pelt of that wattage puts out.