Difference between double and single sided DIMMS

[eeper]

I have two Crucial 512Mb PC3200 DIMMs in my system at the moment. I have been having several stabilty issues with my PC since I installed the second one and yet both memtest fine together and individually.

The only difference between the two seems to be that one has chips on both sides and one has them on just one side. Is this just an aesthetic difference? Or are they not supposed to be mixed? Or maybe supposed to be used only in certain RAM slots on the mobo?

Spec:
MSI K7N2 Delta
Athlon XP3200+
Radeon X850XT 256Mb AGP
Enermax Noisetaker PSU 485W

 

[Defcon5]

i used to have this, i had to sell then as the double sided one didnt work in my new mobo