Dell PowerEdge R905 - Manual (Page 9)

Information Update
7
RHEL Operating System Updates
RHEL Version 4.5 (x86_64) - Support Restrictions for AMD Opteron
Quad-Core Processors (Family 10h)
Red Hat ® Enterprise Linux ® (RHEL) version 4.5 (x86_64) does not support
AMD Opteron quad-core processors Family 10h. For more information,
see http://kbase.redhat.com/faq/FAQ_85_11697.
To avoid potential machine check errors, use RHEL version 5, RHEL version
4.6, or RHEL version 4.5 errata kernel-2.6.9-55-0.12.
RHEL Versions 4 and 5 (x86_64) - System Hangs While Booting
A bug in the APIC initialization code in RHEL version 4 and version 5
(x86_64) could cause your system to hang while booting. If the NMI
watchdog is enabled, the kernel can wait too long for the HPET, resulting
in a system hang. Otherwise, very long boot-up delays can occur.
As a workaround, pass the parameter nohpet to the kernel command line
at system boot, or enter the System Setup program and disable the
High Precision Event Timer (HPET) option on the Integrated Devices screen.
A fix for this issue will be included in RHEL version 5.2.
SLES9 SP4 Boot Issues With AMD Opteron
Quad-Core Processors (Family 10h)
Novell SLES9 SP4 may fail to load on systems configured with quad-core
processors and more than 4-GB of RAM memory. A future maintenance
update from Novell will correct this issue. Currently, you can bypass the issue
by using one of the following methods:
• In the System Setup program, enable the Node Interleaving option
on the Memory Information screen.
• In the operating system boot parameter file, set the memory parameter
to a value less than 4-GB (for example, 3900m).
See the operating system documentation if you need more information.