Process Switching:here router will perform a route table lookup and select an interface and then look for data link layer information...as it is working on perpaket load sharin all packets to the same destination are not send to same interface...
Fast Switching:here router will do table lookup for the first packet and select the exit interface and collect the necessory datalink layer information...and then after for each subsequent packet are directly tranfer to the exit interfac instad of doing table look up for each and every time...
CEF: its like fast switchig and by default use the per destination load sharing...CEF maintain two table FIB forwarding information base which is same as the routing table and adjcancy table which is having datalink layer addresses...In CEF first packet is routed using the table look up and then subsequent packet are tranfer without table look up ...
and i you will not have unequal load balancing in OSPF...
hope this will help you
rate this post if it helps
regards
Devang
