Correction test K7M

J'ai modifié une partie de mon test de l'ASUSTeK K7M. En effet, il est normal que le radiateur censé refroidir les régulateurs de tensions à l'arrière du Slot A ne soit pas fourni avec la révision 1.04 de la carte. Cette dernière est en effet mieux optimisée que les précédentes et ce radiateur n'est donc plus nécessaire.

Please refer to the following explanation to understand why we determine to take out MOSFET heatsink on K7M-1.04.

(1) K7M-1.03 VccCore power layout cause high temperature on capacitors which cannot meet ASUS's spec. of at least 5-years life. In order to pass thermal test and guarantee 5-years capacitors life, we have to install MOSFET heatsink on K7M-1.03 and limit the CPU speed up to 700MHz. We cannot guarantee system thermal and capacitors life beyond 700MHz CPU on K7M-1.03. K7M-1.04 has improved VccCore power layout to significantly reduce the temperature.

(2) K7 Maximum Sustained VccCore Current Estimation: According to our real measurement for sustained VccCore current, K7-700MHz and K7-770MHz (overclocking by 10%) will take around 26.3Amp and 29.1Amp. We can estimate K7-850MHz will take around 32.1Amp. We multiply 32.1Amp by 1.1 to extrapolate the worst current requirement which is 35.3Amp. Therefore, we define 36Amp as the specification for K7 max. sustained VccCore current. Actually, AMD has updated K7 max. sustained core current from 42Amp to 35Amp.

(3) Thermal measurement and capacitors life on K7M-1.04: Test Conditions: Thermal measurement is based on 36Amp VccCore current and running the AMD power test program. AMD power test program will put CPU into the maximum power dissipation mode. Ambient temperature outside chassis is 35 deg. C. If we take out MOSFET heatsink, the temperature on VccCore decoupling capacitors just increase 3 degree C, and MOSFET temperature is still far below specification. The worst temperature and life of capacitors are described as below. The capacitors life meets ASUS's spec. of at least 5 years. So there is no need to install the heatsink.

	1500U/6.3V EC	4700U/6.3V EC	680U/6.3V OS-CON
worst temp.	77 deg. C	76 deg. C	75 deg C
estimated life	6.3 years	8.5 years	6.8 years

Note: Suppose PC working time is 12 hours per day.