Power Consumption @ Like Voltages
This next set of experiments is a bit different. What we did here was lower the .13 micron Newcastle core based processor's voltage to 1.4v to compare total system power consumption while both CPUs were supplied with the same voltage. As you lower the supply voltage, total power consumption should go down (POWER [WATTS] = VOLTS x AMPERES). Keep in mind though, that we were only able to complete this test because our particular Newcastle based CPU, which normally requires 1.5v, was perfectly stable at its stock clock speed with only 1.4v. Should you want to duplicate this test, however, your mileage may vary. There is no guarantee that a Newcastle based Athlon 64 will be stable with a 1.4v core voltage.
(Newcastle @ 1.5v = 26oC @ Idle | 37oC @ 100% load)
(Newcastle @ 1.5v = 91Watts @ Idle | 140 Watts @ 100% load)
As you can see, the Newcastle based 3800+ ran markedly cooler, and used less power with its voltage lowered to 1.4v. The voltage drop, however, wasn't enough to account for the total temperature and power consumption differences between the two different cores. Based on our experiments, it certainly seems that AMD's .09 micron Venice core runs a bit cooler and uses somewhat less power then is .13 micron counterpart.