Quote Originally Posted by HT4U.net
[IMG]http://ht4u.net/images/reviews/2009/power_consumption_graphics//4870_wandler_3.png[/IMG]

Now it is no supprise anymore, why AMD lowers the load synthetically. The card simply can not not bear the load FurMark creates. While the GPU-Temperature is absolutely uncritical, the voltage regulator temperature is not. Meanwhile the datasheet of the voltage regulator is available and Vitec specifies the temperature to 125 degrees.

Via FurMark we reached within a few minutes temperatures from about 125 degrees. Thus we can say: The Radeon HD 4870 definitly has a problem with its voltage regulators when using FurMark. Surely FurMark is a worst-case-scenario, but it points out that the voltage regulators on the Radeon HD 4870 work near its maximum specification.

http://ht4u.net/reviews/2009/power_consumption_graphics/index8.php
That "max 125°C specification" applies only to the Vitec 59PR9853 multiphase inductor. The actual voltage regulators which the "VRM phase [number] temperature" -figures in Rivatuner come from are the Volterra VT1165SF chips - and their max specified operating temp is unknown (datasheet is not public). My point being, those Vitec inductors should run cooler than the Volterra chips since the coil surely consumes only some minute amount of energy (~5W), and as such their temps must be lower than the 120-125°C of the Volterra's which generate a considerably higher amount of heat.