Quote:
Originally posted by JimS
These flow rate arguments are really getting interesting. Here is the way I look at it.
Imagine for a minute that you are taking a small quantity of your coolant, say a droplet and using it as a reference. Say the droplet makes the loop throughout your system in 10 seconds, and spends 2 seconds of that time inside the radiator. In one minute you will have cooled your coolant for a period of 12 seconds. 6 x 10 = 60 seconds, 6 x 2 = 12 seconds.
Now you double your flow rate. Your droplet makes its way through your system in 5 seconds, and spends one second in the radiator. In one minute, you will have cooled your coolant for a period of 12 seconds. 12 x 5 = 60 seconds. 12 x 1 = 12 seconds.
Flow rates in watercooled systems are fairly consistent throughout. There is not a drastic difference in flow rate from any one point in the system to another.
This simple example is why the only thing we watercoolers need to worry about is MINIMUM flow rate. As long as your pump can sustain a flow over 25 gph( this includes the resistance of all the restrictions in a typical watercooled system), your temperature will not fluctuate much no matter how much you increase flow.
There was a test done a while back which pretty much proved this. I think it was an article by Bill Adams from overclockers.com.
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He has since revised his findings to show that a radiators efficiency does indeed increase with increased flow rate albeit on a gradual curve and he only tested up to between 2 and 3 gpm.
I have an extremely high flow rate system (6 gpm) compared to the norm and can say that it is very responsive to airflow at the rad.
Here is a chart of an observance in slight water temp change caused by an increase in airflow at the rad and a subsequent drop in cpu temps after they had stabalized at 42.5C.
9:50 is the idle temps just before the load started. It stabalized at 42.5C at 10:08 with two equal readings of 29.9 water temps. At this point I doubled the fan intake to 100cfm at the rad. Water temps started to drop and by 10:10 a drop in cpu temp was recorded by 10:12.
I used an acurite digital thermometer to record water temps and room temps. Room temps were also compared to a digidoc5 sensor along with the acurite readout. The system stabilizes quickly and responds quickly. There is only a total of a half gallon in the loop which all goes through once every five seconds at this flowrate.