quote:
Originally posted by Wikipedia
The architecture is called x86 because the earliest processors in this family were identified by model numbers ending in the sequence "86": the 8086, the 80186, the 80286, the 386, and the 486. Because one cannot establish trademark rights on numbers, Intel and most of its competitors began to use trademark-acceptable names such as Pentium for subsequent generations of processors, but the earlier naming scheme remains as a term for the entire family.
And also
quote:
A 32-bit address space would allow the processor to directly address only 4 GB of data, a size surpassed by applications such as video processing and database engines, while using the 64-bit address, one can directly address 16777216 TB (more than 16 billion MB) of data.
This is why Vista (and XP) cannot have more than 4GB RAM.