X86 and X64 are just different ways of processing stuff.
not really, they are not really comparible as they are different things,
x86 or 80x86 is the generic name of a microprocessor architecture first developed and manufactured by Intel. The x86 architecture currently dominates the desktop computer, portable computer, and small server markets.
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 trademark numbers, Intel and most of its competitors began to use trademarkable names such as Pentium for subsequent generations of processors, but the earlier naming scheme has stuck as a term for the entire family.
The architecture has twice been extended to a larger word size. In 1985, Intel released the 32-bit 386 to replace the 16-bit 286. The 32-bit architecture is called x86-32 or IA-32 (an abbreviation for Intel Architecture, 32-bit). In 2003, AMD introduced the Athlon 64, which implemented a further extension to the architecture to 64 bits, variously called x86-64, AMD64 (AMD), EM64T or IA-32e (Intel), and x64 (Microsoft).
from wiki