The main catalyst for 64-bit transition is Microsoft’s 64-bit Windows XP operating system possibly due next month. According to the exec of Microsoft, the company aims to ship desktop/workstation version of Windows XP Professional x64 in early April, 2005, with x86-64 flavour of Windows Server 2003 leaving the building in Redmond, Washington in late April, 2005.Microsoft claims 64-bit software can bring more than 35% performance gain for application - while Windows XP x64 could even accelerate 32-bit programs by 15-30% More info at X-bit Labs
Intel: Software industry prepares 64-bit transition

Intel said that the software industry is preparing the transition to 64-bit software.