well - on databases for example you have usually best performance distributing your filesystems or raw devices across as many disks as possible. If you add a bunch of disks you still want them to be...
Hope this helps:
Help - AIX 6.1 Information Center (http://publib.boulder.ibm.com/infocenter/aix/v6r1/index.jsp?topic=%2Fcom.ibm.aix.install%2Fdoc%2Finsgdrf%2Falt_disk_install_examples.htm)
No. AIX only runs on PowerPC hardware. And even if it could run on Intel-compatible hardware you'd still need a license to run it as there's no free/student version available.