If your clock reset when you start your car, then there are two possible problems I can think of.
1. When you run your starter it draws a lot of current , thus stressing the ground cable. If you have a bad or faulty ground off the battery to frame then it could cause your car to rest.
2. There is a circuit that reduces the electrical load when starting. This circuit temporary removes power, like the headlights, while the starter is turning over. Although this is a factory circuit and isn't wired to anything that requires memory.
I would check your grounds, start with the one from the battery. I had the same problem on my 90 G60. The radio and clock would reset occassionaly with the start of the car.
Brian
