Intel E1400 Design Guidelines - Page 69

Intel® Quiet System Technology (Intel® QST) 7 Intel® Quiet System Technology (Intel® QST) In the Intel® 965 Express Family Chipset a new control algorithm for fan speed control is being introduced. It is composed of an Intel® Management Engine (ME) in the Graphics Memory Controller Hub (GMCH) which executes the Intel® Quiet System Technology (Intel® QST) algorithm and the ICH8 containing the sensor bus and fan control circuits. The ME provides integrated fan speed control in lieu of the mechanisms available in a SIO or a stand-alone ASIC. The Intel QST is time based as compared to the linear or state control used by the current generation of FSC devices. A short discussion of Intel QST will follow along with thermal solution design recommendations. For a complete discussion of programming the Intel QST in the ME please consult the Intel® Quiet System Technology (Intel® QST) Configuration and Tuning Manual. Note: Fan speed control algorithms and Intel QST in particular rely on a thermal solution being compliant to the processor thermal profile. It is unlikely that any fan speed control algorithm can compensate for a non-compliant thermal solution. See Chapter 5 and Chapter 6 for thermal solution requirements that should be met before evaluating or configuring a system with Intel QST. 7.1 Intel® QST Algorithm The objective of Intel QST is to minimize the system acoustics by more closely controlling the thermal sensors to the corresponding processor or chipset device TCONTROL value. This is achieved by the use of a Proportional-Integral-Derivative (PID) control algorithm and a Fan Output Weighting Matrix. The PID algorithm takes into account the difference between the current temperature and the target (TCONTROL), the rate of change and direction of change to minimize the required fan speed change. The Fan Output Weighting Matrix uses the effects of each fan on a thermal sensor to minimize the required fan speed changes Figure 7-1 shows in a very simple manner how Intel QST works. See the Intel Quiet System Technology (Intel® QST) Configuration and Tuning Manual for a detail discussion of the inputs and response. Thermal and Mechanical Design Guidelines 69