Paul__B:
A "logic level" FET will turn on at logic levels, but not fully. It really needs about 8 to 10 volts, so you need to under-rate a heavier device to get it to switch on sufficiently for your load.
Ok, thanks, I wasn't aware of that. What info on the datasheet will deliver such information? I really thought a logic level MOSFET would have been fully turned on by a logic level... my bad