Originally Posted by assassin
What case are you using? And what case is your i7 using? How many fans in each? Unless they are using the same case its hard to compare the two as the HTPC case is likely much smaller and crowded.
41C is a decent temperature. If you want to improve that then you can improve case fan flow or the CPU cooler.
My C2D in the cavernous Antec NSK2480 case with a Geminii S cooler and 2 large case fans idles in the mid 30s. The fanless 5450 video card idles around 45-50c.
If 41C idle is reasonable for the i3 in an HTPC environment, then I will probably stick with the stock fan for now, get the unit up and running under the TV, and try it out for a few weeks. If the fan noise is not objectionable in regular usage, and temps do not spike, then I probably won't bother doing anything about it.
For reference, my .Net development/video editing rig uses the i7-950 (130 watt CPU) in an Antec 300 case, which has two 120mm fans in the front, one 120mm fan in the back, one 140mm fan at the top, and the well regarded (but generally too large for an HTPC case) CoolerMaster 212+ Hyper CPU cooler. All fans are set to low, and the unit is quite and cool, with the CPU idling around 30C.
The new HTPC rig I am building is as you suggest, a bit more crowded inside, and does not have the same opportunity for mass air flow. It is using the nMedia 1000B case with fewer and smaller diameter fans. But even with the case top removed, and only after a few minutes of having been turned on, the CPU temp is already idling around 41C. Sounds like that temp might be normal with the provided CPU cooler.