No you are not right. 32 bit OS can use theoretical 4 GB. Becurse when the processor use 32 buses (adress bus , Data bus, etc) it can only adressing 2^32 Bytes, and this is a maximum of 4 GB (2^32 is 4294967296 Byte and that are 4 GB for useing) but in realty is it 3,3 GB ( I dont know why it is so). And with 64 bit is is more (2^64 is 1844674407309551616 Byte and that are 16777216 TB or 16 ZB (Zetta Byte , 10^21))

Bye

White_Wolf