I've installed kubuntu 14.04, and there is some problem with CPU turbo frequency. I've read a lot about it, but can't find the correct answer.
There is an i7-3630QM CPU @ 2.40GHz with 3.20GHz turbo in my Lenovo Y580 notebook. If i put the cpu at full load (with rendering in blender on 8 threads) the frequency jumps to around 3.2GHz for all cores, but after a few seconds, when the temperature rises, the frequency decreases to 2.4GHz, and stay on it during the rendering, (the fan does not run at max speed).
When i used ubuntu 12.10 this problem not occured, but it does in 13.10 and 14.04.
My notebooks cooler is really good, so there is no toverheating problem with the full speed turbo boost (the cpu temp was 85-90°C at 3.2GHz in ubuntu 12.10), so i want to use it on full speed. How can i use the cpu with turbo boost at full 3.2GHz speed in ubuntu 14.04 without this (temperature?) limit?
(after discuss with terdon) I think the problem is that cpu freq is scaled down before the fan could respond to the high temperature. AFTER cpu scaled back from 3.2GHz to 2.4GHz the fan spins up for a moment, but because cpufreq already scaled down, it generates less heat, so the fan's rpm falls back. It would be ok, if after cpu cooling down, frequency rise again to 3.2GHz, but it stays on 2.4GHz.
Some measurements:
Output of i7z program, when the render just started:
Cpu speed from cpuinfo 2394.00Mhz
cpuinfo might be wrong if cpufreq is enabled. To guess correctly try estimating via tsc
Linux's inbuilt cpu_khz code emulated now
True Frequency (without accounting Turbo) 2394 MHz
CPU Multiplier 24x || Bus clock frequency (BCLK) 99.75 MHz
Socket [0] - [physical cores=4, logical cores=8, max online cores ever=4]
TURBO ENABLED on 4 Cores, Hyper Threading ON
Max Frequency without considering Turbo 2493.75 MHz (99.75 x [25])
Max TURBO Multiplier (if Enabled) with 1/2/3/4 Cores is 34x/33x/32x/32x
Real Current Frequency 3192.01 MHz [99.75 x 32.00] (Max of below)
Core [core-id] :Actual Freq (Mult.) C0% Halt(C1)% C3 % C6 % C7 % Temp
Core 1 [0]: 3191.98 (32.00x) 100 0 0 0 0 83
Core 2 [2]: 3192.01 (32.00x) 99.8 0 0 0 1 92
Core 3 [4]: 3192.00 (32.00x) 100 0 0 0 0 88
Core 4 [6]: 3192.00 (32.00x) 100 0 0 0 0 76
...
And 5-10 seconds later (also with full load):
Cpu speed from cpuinfo 2394.00Mhz
cpuinfo might be wrong if cpufreq is enabled. To guess correctly try estimating via tsc
Linux's inbuilt cpu_khz code emulated now
True Frequency (without accounting Turbo) 2394 MHz
CPU Multiplier 24x || Bus clock frequency (BCLK) 99.75 MHz
Socket [0] - [physical cores=4, logical cores=8, max online cores ever=4]
TURBO ENABLED on 4 Cores, Hyper Threading ON
Max Frequency without considering Turbo 2493.75 MHz (99.75 x [25])
Max TURBO Multiplier (if Enabled) with 1/2/3/4 Cores is 34x/33x/32x/32x
Real Current Frequency 2462.52 MHz [99.75 x 24.69] (Max of below)
Core [core-id] :Actual Freq (Mult.) C0% Halt(C1)% C3 % C6 % C7 % Temp
Core 1 [0]: 2394.01 (24.00x) 100 0 0 0 0 65
Core 2 [2]: 2394.00 (24.00x) 100 0 0 0 0 74
Core 3 [4]: 2462.43 (24.69x) 100 0 0 0 0 71
Core 4 [6]: 2462.52 (24.69x) 99.9 0 0 0 0 61
...
Thanks in advance for the answers.