the installation of OS/2 / eCS still has some problems. OS/2 4.50 probably won't install at all because IBM does not change much anymore on OS/2. For eCS 1.2 (the successor of OS/2 for private customers, s. www.ecomstation.com) there is already a Beta version which installs on AMD 64 machines.
But: All I have said is only true for installing. If you install OS/2 or eCS on another machine and then put this harddisk into an AMD Athlon 64 machine (nearly) everything works fine. Nearly means some new onbaoard audio- and lan-chips are not working fine or not at all and there are some problems with PCI-SCSI- and PCI-LAN-cards: The timing seems to be to fast in NForce4 PCIe/PCI-Boards.
Hans v. Mangoldt.