These workstations are powered by AMD Opteron chips. The older 20 and 40 models use single-core processors, while the newer M2 line uses dual-core CPUs.
Novell is not the first to bring Linux to the Ultra line. Canonical, following on up the deal that brought Ubuntu to the UltraSPARC T1 processor on Sun Fire T1000 and T2000 servers, started testing Ubuntu on Suns AMD-powered Ultra series last November.
RHEL 4 (Red Hat Enterprise Linux) is also available on these systems as an option. The newest Red Hat Linux, RHEL 5, however, is not yet available on them.