Suddenly today - I can't really pinpoint when - my CPU has become locked at a low frequency, even under load. I hadn't changed any settings in Windows 8.1 or in the BIOS, and everything appeared to be set as it needed to be. This is a desktop, and the power settings are set to maximum performance.
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The standard speed on this processor is 3.2Ghz, but it is limited to 1.34. I tested using some demanding programs I have used within the past few days and confirmed that the CPU load, temperatures, and fan speeds did not increase significantly, and performance was significantly decreased.
I've tried the amd/intelppm.sys "fix", but this appears to be only a placebo. Windows Task Manager shows that the speed is at maximum, but the behavior is as before, and Open Hardware Monitor reflects the lowered clock speed. I have also tried disabling AMD Cool n Quiet and changing the clock speed in the BIOS, without success, though I haven't had any problems before. I checked on Linux Mint installed on another partition, and /proc/cpuinfo seemed to suggest that the normal ramping up behavior of the clock speed was working, however neither the fan speed nor the temperatures increased, so I suspect it was not "real."
Summary
Operating System
Windows 8.1 Pro 64-bit
CPU
AMD FX-8320E 28 °C
Vishera 32nm Technology
RAM
16.0GB Dual-Channel DDR3 @ 933MHz (13-11-11-29)
Motherboard
MSI 970 GAMING (MS-7693) (CPU 1) 34 °C
Graphics
24M45 (1920x1080@60Hz)
2048MB ATI AMD Radeon R9 380 Series (MSI) 41 °C
Storage
931GB Seagate ST1000DM003-1ER162 (SATA) 41 °C
Audio
AMD High Definition Audio Device