> Cent OS 5.5 x64 does not boot on certain AMD-based servers. Following error > is displayed: > > Code: 8b 72 40 48 8d 4c 24 1c 48 8b 7a 20 ba c4 01 00 00 e8 5f 77 > RIP [<ffffffff8008192f>] cpuid4_cache_lookup+0x256/0x356 > RSP <ffff810104737d60> > CR2: 000000000040 > <0>Kernel panic -- not syncing: Fatal exception > This issue was noticed on Dell PowerEdge R715 with AMD Opteron 12-core > processor. Is there any kernel specific patch which addresses this issue? Have you tried installing the most recent release (5.8 or 6.3 depending on your requirements)? 5.5 is pretty ancient and only the current code is supported for a given major revision number (ie CentOS5 or CentOS6 at this time given that CentOS5 is now end of life).