Influence of The Performance Setting Of The CPU
From Jacket Wiki
Many modern CPUs can be controlled dynamically with respect to for example the clock frequency. In Microsoft Windows 7 Enterprise x64 it is possible to adjust the CPU performance dynamically. Generally, the power scheme should always be set to 'High Performance', which by default gives 100% CPU performance for both minimum and maximum. To see the effect of controlling the minimum setting of the CPU performance, the 'High Performance' scheme was chosen but with minimum CPU performance set to 20%. The application used is the DGeMM technique to estimate the floating point performance in double precision. The figure below compares the result for a minimum setting of 20% and 100% for the CPU, and the GPU used was an NVIDIA Tesla C2050.
As seen from the figure the two results agrees fairly well for most array sizes. However, from matrix size at approximately 900x900 to size 1400x1400 the performance clearly drops. Since the only difference is the setting of the CPU performance, the frequency has most likely been reduced. The temperature was subjectively clearly high, which may be a possible although not definite explanation. The same jump in performance happens again at higher array sizes. The GPU is affected just a tiny bit - it can be seen that there is a small drop in GPU performance when the CPU performance drops - but it is minor.
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