RE: My Gridcoin Journey
There is no practical difference between running 24/7 and sporadic loads. Under 24/7 load, water gets heated rather quickly to approximately 15 degrees over room temperature (all measurements taken on my rig) but it isn't "satiated", it's still much cooler than the CPU and the GPU and its cooling capacity is affected very little, for all practical purposes.
Fans don't have to turn faster when the water is warmer, that's completely absurd. Heat transfer in the radiator is simply increased through larger temperature difference between the air (which is at constant room temperature) and the water. As the water gets warmer, heat transfer from the water to the air is increased even further and the water cooling system enters into an equilibrium naturally.
Vardar fans noise level at 1850 rpm is rated at 29.5 dBa which is again quite silent for all practical purposes. Of course, there are even less noisy fans on the market (for example Gentle Typhoons which even had 500 rpm models). Overall, compared to air cooling, watercooling is practically noiseless.
About the first two points - as i said - you are right and wrong at the same time but i don't wan't to hold a dissertation about heat capacity now.
The last point however is wrong (or outdated, some years ago your statement was correct), air cooling can be as silent as water cooling, e.g. BeQuiet SW3 fans have only 28.6 dBa at 2200 rpm, at 1850 consequently less dBa and this with a massive air flow capacity.
For watercooling i prefer Noctua fans, more static pressure and airflow then Vardar with less dBa but you need to decide if the higher cost justifies the 1-3 degrees celsius less temperature compared to Vardar fans.