Temp in the water loop?

[rithina]

May I ask what is usually the normal temp inside a water cooling loop? Let say my GFX is under water at full load around 70 degree.. Is it means that the water in my tube is at least 70 degree too before going thr the radiator? :)

[creidiki]

nah... my water never goes above 30c, load temp on the x1900xtx oced is over 40...

[freecableguy]

Heat travels from mediums of high temperature to low(er) temperature ONLY. Therefore in order for heat to travel from your GPU to the water, the water must enter the waterblock at a temperature of less than 70F if it will keep your card at a GPU temperature of 70F at full load.

The coolest that the water can enter the waterblock is also dependent on ambient temperature. Since heat travel FROM the water requires that the room temperature be LESS than the water temperaure this further bounds temperatures...

Now, since watercooling has no work input to the system (W=0) it stands to reason that subambient cooling is not possible. (Which we know is true!) So...the room temperature MUST be at MOST 70F.

NOTE: This reasoning holds up in all cases. Your temperaures reported by your GPU may be a little off so don't think you are breaking the laws of thermodynamics here if something doesn't quite work with your observed temps. ;)

Here's what we get:
temp GPU > temp water > temp room
(for heat transfer to occur)

Therefore: the water leaving the block is LESS than 70F. :D

-FCG