The Lab and most other viewer authors are building 32-bit programs. We are seeing more people building 64-bit viewers. The Lab has yet to move that direction with their Second Life™ Viewer. The stats coming out of the Lab show that 64-bit versions are way more stable or in plain English; crash less often.
The game PlanetSide 2 is discontinuing support for 32-bit systems. Specifically their new version of the game will only run in a 64-bit operating system. Massively OP mentions it in their article: Planetside 2 Discontinues Support For 32-Bit Client. The game managers realize some people will be locked out of the game. From there stats it is ‘a very few people.’ Management presumably feels keeping up with technology is worth the cost of losing a small number of users.
The Lab has not been making any noise about building their own 64-bit viewer. But, they make it plain the 32-bit viewer runs much better in a 64-bit operating system.
When will the Lab consider a 64-bit viewer? I suspect not any time soon. When asked they tend to point to the funner things they want to work on.
What about Project SANSAR? I am betting it will only be 64-bit. Ebbe started the Project to avoid legacy issues while advancing the Lab’s virtual world. Now-a-days a 32-bit CPU is considered a legacy device.
In the PC desktop world 64-bit CPU’s arrived in 2003 and became ubiquitous in 2004. Computers generally last less than 10 years. A few last longer. Others are repaired and the owners hang on. But, the majority of computers are now at least 64-bit capable.