AMD Phenom(tm) II x4 20 Processor

KiloLAN #2 started in Espoo this weekend and we enjoyed the top gamers from Hungary, South-Korea and Finland. During games we also checked if the rumours are true about Phenom2 core unlocking.

cpuinfo was showing that test server was running with 3 cores even if physically the CPU is a quad-core circuit.

[root@lnx ~]# cat /proc/cpuinfo
processor       : 0
vendor_id       : AuthenticAMD
cpu family      : 16
model           : 4
model name      : AMD Phenom(tm) II X3 720 Processor

We rebooted the machine, went to BIOS and looked for cpu-setting NVIDIA Clock Calibration, which was Disabled by default. The setting was changed to Auto and Cool'n'Quiet technology was set to disabled. Then PC rebooted once again and cpuinfo was telling the following.

[root@lnx ~]$ cat /proc/cpuinfo
processor       : 0
vendor_id       : AuthenticAMD
cpu family      : 16
model           : 4
model name      : AMD Phenom(tm) II X4 20 Processor

Oh yes, 4th core was running, but the bad news is that the fourth core was not stable. All the CPUs are unique when it comes to overclocking and this time there was no luck in Kilo-office. BIOS was then reset to default 3-core setup and CPU was overclocked slightly from default 2.8 GHz to 3.2 GHz.

[root@lnx ~]# cat /proc/cpuinfo
...
cpu MHz         : 3200.399

At the same time workstation was overclocked from 2.8 GHz to 3.8 GHz where it was still stable.