Ah, because of the pci-e slot? Well now, that's not entirely true.
You can mod it, cut two rows that align with the slot and bend the rest a little (i had a picture of it around here, i'll see if i can dig it up). Involves work, thou, but it works great (afaik).
Anyway, NB's are getting hotter thou. Mine does, and it's better to be safe specially if you're increasing the chipset voltage, althou a dual mobo usually is short on those "features". Just saying. I sticked a mcw20 on mine anyway (had room).
Probably not worth it if you're not touching the chipset voltage. Probably.
If you're really picky about it, you can use a Freezer:
http://www.techpowerup.com/reviews/Mips/DFIFreezer