Well, the specs (from Samsungs webpage or elsewhere) suggest so (notebook HD), but you have to remember: laptops (and certainly Apple’s) are manufactured tightly, so that eg heat flow is very precisely regulated for the original drive. Replacing something like a HD may mess up the heat flow. So a heat problem (if any at all) would be in the configuration as a whole, not the HD by itself. For starters, you could try and compare the temperature specs for the old and new HDs: if the new one releases much more heat, the iBook may simply not be able to cope with it properly. You could search for other people having done something similar, and what their results where.