On Wed, 13 Jul 2011, John R Pierce wrote: > for many things, 32bit code is more compact and runs faster than 64bit > code (primarily because the code is smaller, so it requires fewer > fetches, more code fits in the cache, etc). 64 bit OS's totally > compatible with 32bit applications. of course, if a process needs more > than a couple gigabytes of address space, then 64bit is a no-brainer, > but there's really not that many applications which need that sort of > memory. Is that generally true? I thought running in 64bit got you access to twice as many registers and that generally you'd expect better performance from x86_64 code not worse. While pointers would be doubled in size, most of your memory consumption would boil down to base types that'd be of the same size. jh