the flashy Asus D510 board is ... more expensive. Maybe I should buy one and see how passive cooling works with that heatsink.
Well, its price has dropped around here. Here's how the AT5NM10-I compares to the D510MO then:
-bigger, mean-looking heatsink which covers the NM10 chip as well as the CPU
-higher reported CPU temperatures
-much lower reported MB temperatures
-doesn't work too well when positionned horizontally
The problem with interpreting the reported temperatures is that I doubt the sensors are located in equivalent positions and the meaning of the readings is somewhat elusive (to me anyway). In spite of the low MB temperatures reported by the Asus, a lot of components were hot enough to hurt. In horizontal operation (with an open case so that I could touch the electronics), the heasink itself got suspicously hot under load in spite of moderate temperatures being reported (60 C for the CPU).
It's an improvement over the stock D510MO in some respects but I'm not crazy about the thermals of the Asus (with a sample size of 1, mind you). I don't mind it too much that the CPU reports >70C when the D510MO's readings only reach 50C in the same situation. These CPUs are supposed to get hot. But, while the reported MB temperatures are good (in contrast to the D510MO's) my fingers tell me something somewhat different.
If you believe that the hot NM10 chip deserves a heatsink and you don't want to fit one yourself, the Asus board might be a good choice. Just make sure it's going to be positioned vertically.
The above applies to fanless operation obviously.