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One for the pro's. "Watercooling"

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swanie

New Member
Joined
Jun 22, 2001
Hi there

I wonder if any of you know what the C/W is for an alluminium waterblock?

Lets say my room temp is = 21c
my water temp is = 25c
my cpu temp is = 46c (according to mobo)
My Watt is = +/- 63

I'm running a t'bird [email protected] 133x9=[email protected]
 

wildone

Senior Member
Joined
Mar 7, 2001
Location
TN
download radiate you can get it from the front page of oc.com ,I will get a link
Not sure about the answer off the top of my head but just wanted to say welcome to the forums
wildone
 

AMDGuy

Member
Joined
Apr 10, 2001
swanie (Jun 22, 2001 08:05 p.m.):
Hi there

I wonder if any of you know what the C/W is for an alluminium waterblock?

Lets say my room temp is = 21c
my water temp is = 25c
my cpu temp is = 46c (according to mobo)
My Watt is = +/- 63

I'm running a t'bird [email protected] 133x9=[email protected]

With the numbers you posted C/W is .39. I'm sure this is off as you posted "room temp" when "ambient temp" is needed for the equation. Ambient is usually measured 1" from the processor. The formulae is
Delta = CPU Temp - Ambient Temp
C/W = Delta/Watts

Hope this helps. Definitely download radiate!
 
OP
S

swanie

New Member
Joined
Jun 22, 2001
THX Chaps

So all in all... the waterblock is not that good unless you use it with a peltier or by keeping the water temp as low as possible... say 15c.

I've seen HSF with a lot lower C/W....around .25 and .18
Hmmmm....wonder if lapping the block would bring the C/W down....
Any advice would be appreciated.
 

Thelemac

Administratively Deficient
Joined
Mar 15, 2001
Well, that's not your actual C/W as you didn't really measure the temps right. You would have to measure them for ambient 1" from the top and for cpu stick a thermlecouple next to the die (good enough for this, though a reviewer should probably do it to AMD's specs).

This was mentioned above, but you apparently didn't pay attention. The temps you are using aren't really good enough to determine actual performance to the level you are looking for. They are good enough to decide if your cpu is going to die.

Lapping would help if it wasn't done at the factory and if there was some damage done to the bottom of the block (scratches or what have you)
 
OP
S

swanie

New Member
Joined
Jun 22, 2001
Hi again.

I just cant understand what the ambient temp has got to do with watercooling as it is the water that is cooling the block and not a fan.

I understand the whole concept of checking the temps when it comes to air cooled units, but I am sure it must be different for water cooling.
 

Thelemac

Administratively Deficient
Joined
Mar 15, 2001
There isn't any difference, cause the ambient temp is the goal...water isn't going to go below that without somewhat extreme measures. Since that's the goal, you check the temp of the processor and subtract the ambient temp to get how much the water is able to cool the processor (actually the water is cooling the waterblock, as it doesn't actually come into contact with the cpu, but that's really just nitpicking on my part) and when you divide that by the watts your cpu is putting out you get how well the waterblock is able to remove the heat (so the units of c/w are degree C per watt given off)...

I hope this makes it clear to you. :)
 

rugby

King of Cats Senior
Joined
Feb 2, 2001
Location
Chicago, IL
swanie (Jun 24, 2001 06:04 p.m.):
Hi again.

I just cant understand what the ambient temp has got to do with watercooling as it is the water that is cooling the block and not a fan.

I understand the whole concept of checking the temps when it comes to air cooled units, but I am sure it must be different for water cooling.

Hi there, ambient temps have EVERYTHING to do with watercooling because you are still using a fan to cool if you have a radiator. My water setup consists of a waterblock, radiator, 120mm fan, and in-line pump/reservoir. THe water leaves the reservoir, goes to the waterblock on the cpu, and then goes to the radiator which is copper tubing with little fins on it. There is a 120mm fan attached to the radiator, drawing air through the radiator to cool the water. If the air in the room is really cold, the water is cooled more. THAT's the importance of ambient air temps. Here's a pic that shows a fan and radiator:
 

AMDGuy

Member
Joined
Apr 10, 2001
rugby (Jun 24, 2001 08:19 p.m.):
swanie (Jun 24, 2001 06:04 p.m.):
Hi again.

I just cant understand what the ambient temp has got to do with watercooling as it is the water that is cooling the block and not a fan.

I understand the whole concept of checking the temps when it comes to air cooled units, but I am sure it must be different for water cooling.

Hi there, ambient temps have EVERYTHING to do with watercooling because you are still using a fan to cool if you have a radiator. My water setup consists of a waterblock, radiator, 120mm fan, and in-line pump/reservoir. THe water leaves the reservoir, goes to the waterblock on the cpu, and then goes to the radiator which is copper tubing with little fins on it. There is a 120mm fan attached to the radiator, drawing air through the radiator to cool the water. If the air in the room is really cold, the water is cooled more. THAT's the importance of ambient air temps. Here's a pic that shows a fan and radiator:

Be careful here. Don't confuse "ambient" and "room" temps. Ambient is measured 1" from the processor. Room temp would be measured at the intake to the radiator. These will likely be different temps. For instance my "ambient" is around 32 C. Room temp is around 26 C. You have to consider actual ambient temp for the C/W equation because thermal properties dictate that at higher temps heat transfer is less efficient.
 
OP
S

swanie

New Member
Joined
Jun 22, 2001
Hi

Wow... what a response :)
Thx chaps. Now that I have the answers I can move on to greater things :)

2 thumbs up to overclockers.com