From which you measure the ambient? The case temperature or the water?
I think it should be measured from the water, as when you're calculating a HSF C/W, you measure the temperature of the medium used to remove the heat from the HSF. Which is air with heatsinks.
I think it should be measured from the water, as when you're calculating a HSF C/W, you measure the temperature of the medium used to remove the heat from the HSF. Which is air with heatsinks.