Linux – CPU error messages shown in console during boot — “CPU1: Stuck ??”

I recently installed a second CPU into a server. The CPU is identical to the first and I verified that the CPU is in good working order prior to the installation.

The server booted up and I installed CentOS 6 without issue.

The POST screen recognizes both CPUs — screenshot: http://pasteboard.co/bOY8M04.png

However, upon first boot I noticed a strange error message on the console showing "CPU1: Stuck ??" — screenshot: http://pasteboard.co/bOWvk1c.png

Upon digging through the /var/log/messages, I found more debug output on this error:

Sep 13 18:01:58 customer kernel: Kernel panic - not syncing: Fatal exception
Sep 13 18:01:58 customer kernel: Pid: 0, comm: swapper Tainted: G      D    ---------------    2.6.32-431.29.2.el6.x86_64 #1
Sep 13 18:01:58 customer kernel: Call Trace:
Sep 13 18:01:58 customer kernel: [<ffffffff8152873c>] ? panic+0xa7/0x16f
Sep 13 18:01:58 customer kernel: [<ffffffff8152ca74>] ? oops_end+0xe4/0x100
Sep 13 18:01:58 customer kernel: [<ffffffff81010e0b>] ? die+0x5b/0x90
Sep 13 18:01:58 customer kernel: [<ffffffff8152c552>] ? do_general_protection+0x152/0x160
Sep 13 18:01:58 customer kernel: [<ffffffff8152bd25>] ? general_protection+0x25/0x30
Sep 13 18:01:58 customer kernel: [<ffffffff8103eb79>] ? native_write_cr4+0x9/0x10
Sep 13 18:01:58 customer kernel: [<ffffffff81050a2e>] ? syscall32_cpu_init+0x6e/0x80
Sep 13 18:01:58 customer kernel: [<ffffffff8151bea2>] ? xsave_init+0x31/0x48
Sep 13 18:01:58 customer kernel: [<ffffffff8151be45>] ? fpu_init+0x7e/0xaa
Sep 13 18:01:58 customer kernel: [<ffffffff8151df1b>] ? cpu_init+0x309/0x35f
Sep 13 18:01:58 customer kernel: [<ffffffff81521fcd>] ? start_secondary+0xd/0x2ef
Sep 13 18:01:58 customer kernel: [<ffffffff81521fc0>] ? start_secondary+0x0/0x2ef
Sep 13 18:01:58 customer kernel: CPU1: Stuck ??
Sep 13 18:01:58 customer kernel: #2 #3
Sep 13 18:01:58 customer kernel: general protection fault: 0000 [#2] SMP
Sep 13 18:01:58 customer kernel: last sysfs file:
Sep 13 18:01:58 customer kernel: CPU 3
Sep 13 18:01:58 customer kernel: Modules linked in:
Sep 13 18:01:58 customer kernel:
Sep 13 18:01:58 customer kernel: Pid: 0, comm: swapper Tainted: G      D    ---------------    2.6.32-431.29.2.el6.x86_64 #1 Supermicro X7DWT/X7DWT

Here is a full output of the /var/log/messages during boot: http://pastebin.com/b3wfmLX6

After the system boots, if I run a cat /proc/cpuinfo only four cores are shown.

Does anyone know what could be causing these errors?