All -

I have received several HP DL385 / Opteron 252 servers and getting ready to install Redhat ES 3.  My question is do I need to install the x86_64 version of rhel to truely take advantage of the hardware, or can I install the standard 32-bit version?  Outside of NUMA, what other advantages do I have by installing the x86_64 version.  Does the x86_64 bit version ship with all the standard 32-bit compatible libs.  If I have developers that have written code on a standard RHEL3, will the compile w/o issue in the x86_64?

Thanks for your help
JD