*** This bug is a duplicate of bug 1480349 *** https://bugs.launchpad.net/bugs/1480349
Public bug reported: Recently my system became really sluggish - turned out that all 12of my CPU cores were running at about 400Mhz, despite the hardware limits reported by cpufreq-info: hardware limits: 1.20 GHz - 3.20 GHz Setting the governor to "performance" did not help. Then I noticed that there is an unkown driver marked as active besides the NVIDIA drivers: "Using Processor microcode firmware for Intel CPUs from intel-microcode (proprietary)" Disabling this driver and rebooting fixed the performance issues and CPU frequencies are now normal. $ uname -a Linux 3.19.0-25-generic #26-Ubuntu SMP Fri Jul 24 21:17:31 UTC 2015 x86_64 x86_64 x86_64 GNU/Linux $ lsb_release -rd Description: Ubuntu 15.04 Release: 15.04 $ apt-cache policy intel-microcode intel-microcode: Installed: (none) Candidate: 3.20150121.1 $ cat /proc/cpuinfo processor : 0 vendor_id : GenuineIntel cpu family : 6 model : 63 model name : Intel(R) Xeon(R) CPU E5-2620 v3 @ 2.40GHz stepping : 2 microcode : 0x25 cpu MHz : 2912.343 cache size : 15360 KB physical id : 0 siblings : 12 core id : 0 cpu cores : 6 apicid : 0 initial apicid : 0 fpu : yes fpu_exception : yes cpuid level : 15 wp : yes flags : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe syscall nx pdpe1gb rdtscp lm constant_tsc arch_perfmon pebs bts rep_good nopl xtopology nonstop_tsc aperfmperf eagerfpu pni pclmulqdq dtes64 monitor ds_cpl vmx smx est tm2 ssse3 fma cx16 xtpr pdcm pcid dca sse4_1 sse4_2 x2apic movbe popcnt tsc_deadline_timer aes xsave avx f16c rdrand lahf_lm abm ida arat epb pln pts dtherm tpr_shadow vnmi flexpriority ept vpid fsgsbase tsc_adjust bmi1 avx2 smep bmi2 erms invpcid xsaveopt bugs : bogomips : 4789.35 clflush size : 64 cache_alignment : 64 address sizes : 46 bits physical, 48 bits virtual power management: (...) ProblemType: Bug DistroRelease: Ubuntu 15.04 Package: intel-microcode (not installed) ProcVersionSignature: Ubuntu 3.19.0-25.26-generic 3.19.8-ckt2 Uname: Linux 3.19.0-25-generic x86_64 NonfreeKernelModules: nvidia ApportVersion: 2.17.2-0ubuntu1.1 Architecture: amd64 CurrentDesktop: Unity Date: Thu Aug 6 14:21:13 2015 InstallationDate: Installed on 2015-07-14 (22 days ago) InstallationMedia: Ubuntu 15.04 "Vivid Vervet" - Release amd64 (20150422) SourcePackage: intel-microcode UpgradeStatus: No upgrade log present (probably fresh install) ** Affects: intel-microcode (Ubuntu) Importance: Undecided Status: New ** Tags: amd64 apport-bug vivid ** This bug has been marked a duplicate of bug 1480349 Breaks frequency scaling in Xeon® E5-2687W v3 -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1482221 Title: Intel CPU is forced to 400Mhz on all cores To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/intel-microcode/+bug/1482221/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs