The RC040 likes to be accompagnied by a heat sink, especially if you might do the 33 MHz hack on the 475. Some processors have the heat sink glued in place, some come with a removable heat sink fixture to be mounted when inserting the CPU into the socket. If you have to mount a heat sink, apply some thermal conductive paste/glue or thermal conductive adhesive on top of the CPU before seating the heat sink. In case you use electrical conductive paste, carefully avoid to produce shorts (which could come from some paste spread onto the mainboard).

Check clearance of heat sink to case and memory module _before_ glueing it in place ;-)