64 Bits are Overrated

"I think they are doing a marketing gimmick. There's zero benefit a consumer gets from that. Predominantly... you need it for memory addressability beyond 4GB. That's it. You don't really need it for performance, and the kinds of applications that 64-bit get used in mostly are large, server-class applications." -- Anand Chandrasekher

most desktop apps never use more than 1 gigabyte of memory (mostly due to the von-neumann bottleneck). And 32bit still allows using more than 4 gigs of memory:
http://en.wikipedia.org/wiki/Physical_Address_Extension

So basically 64 bits just waste transistors.

>>1
PAE a shit. Having a physical address space that's larger than the virtual space means the OS will fuck itself sideways managing the page mappings. DOS did this when the 386 was introduced and it doesn't suck any less now than it did then.

>>7
Word size on x86 is variable. In practice though one always tries to use the default size because the instruction encoding to change the operand size is inefficient. That limitation applies no matter what language you happen to use.

Other ISAs don't impose this encoding penalty, and C language code written with this in mind works fine on them.

>>11
No one is stopping you from running 32 bit applications on a 64 bit OS if you know 3-4 GB per process is all you need.