Chris Ng, FWIW, there is a big chance that the issue you observed is ultimately caused by thermald depending on weakly specified behavior that is known to be processor-model-specific, and which we now know to be also microcode-level specific.
Please refer to bug #1480349, and remove thermald from your system. Don't run thermald on any Xeon boxes. Removing thermald has a good chance of fixing the issue you observed, as the modified Ubuntu version that detects and refuses to run on Xeon boxes had not yet been sucessfully backported to vivid-lts at the time I wrote this reply. A reboot is required after removing thermald, to ensure all processor MSRs are reset to firmware/kernel defaults. If you do test the new microcode with thermald removed, please drop us a note on this bug report. Other users find this bug report through Google, and the information would be helpful to them. If removing thermald does NOT fix your issue, I would really like to know about it to further try to debug this issue. -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1506050 Title: intel cpu frequency is stuck at ~400mhz To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux-lts-vivid/+bug/1506050/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
