Intel T7800 vs X9000 in terms of heat

Does anyone know the the difference in terms of heat between these two processors?

The T7800 (65nm) has a TDP of 35w and the X9000 (45nm) has a TDP of 44w. I don't think the TDP for the T7800 is representative of the heat it actually produces though. Other Merom's also have the same TDP rating, but run much cooler since they are clocked slower.

The Intel spec sheet also says the X9000 uses about the same power. 1.0-1.15v or 1.0-1.275v depending on the spec sheet you look at. The T7800 uses 1.0-1.25v.

 

Think of the TDP rating as the 'budget' for a heatsink/cooler setup. Whatever setup is used for a heatsink/cooler, it MUST be able to cool down the cpu assuming a constant heat input of XX watts.

In electronics, TDP is a common measurement and specification of internal heat production and yes, it is measured in watts. Remember that watts are an instantaneous point-in-time measure of **energy**, not necessarilly electrical energy. Heat is energy.

BtUs are another measurement of energy, but time is also factored in.

TDP bears little relationship to actual power consumption or clock speed. It can be used as an indicator of how efficient a given cpu may be in terms of power consumption and heat generation. But it is mostly a HEAT measurement.

In a tightly integrated/closed environment like a laptop chassis, heat management is a major design factor.

 

They give the X9000 a 44w TDP because it is an extreme edition processor with an unlocked multiplier and can be clocked as high as the user can get it to go. There is a linear relationship between clockspeed and power consumption, and a square relationship for voltage and power consumption. There is also a linear relationship between temperature and power consumption. On top of that, the X9000 uses an older stepping of the penryn than do most other mobile penryn chips. The older stepping has slightly higher power consumption than a comparable newer stepping. However, it is still better than a merom in this regard.

 

in a perfect, white-lab-coat world those relationships hold true. the basic relationships between voltage, frequency, amps, and watts have been known for what, almost 200 years now.

in semiconductors where you also have to deal with substrate materials, lots of capacitance & resistance, and less than optimal cooling, the lab formulae get thrown out for more sophisticated measurements.