How is a 64bit AMD pc different from a Pentium 4 28ghz pc and which is better for multimedia jobs?

Answer 1

The Pentium 4 is 32bit and while 64bit helps, most older programs are written for 32bit.  Multimedia requires speed and power so either AMD or Intel with large on-die cache is what's needed.  Dual core from either is the best but my preference is AMD as generally the L2 on-die cache is larger at 1mb per core.