Is it necessary to deactivate the dynamical clock rate feature of modern CPU types?

 No, WinCC OA can be used on computers where this feature is enabled.

Altough the following considerations have to be taken into account.

Modern CPU types (like Intel i7, Intel XEON, AMD FX, AMD Opteron) are changing the CPU-frequency for every core based on the current load. The common names for this feature are
-- "Turbo Boost Technology" for Intel processors
-- "Turbo Core" for AMD processors

In high load scenarios a single core can be overclocked to allow one process to use more CPU power. This can be useful in productive use if a single process needs more power for a short period of time.
If the current load is very low the clock rate could also be decreased to save power (environmental considerations).

This feature could be disturbing when doing load tests or when trying to compare perfomance data between different system or different load scenarios.
There are different type of load tests which are usually carried out to check if the selected hardware can be used for the productive system:
-- performance for a constant load
-- determination of the highest possible load

To get comparable numbers for the CPU-load in such a case we recommend to deactivate this feature at the BIOS settings for the used computers. If the feature is deactivated the CPU is running with a constant CPU-frequency.

For details concerning the BIOS-configuration or the functionality of this feature please get in contact with your system administration or the hardware vendor.