[CentOS] centos 64 bit

[John Hodrien]

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