Power & Thermal Characteristics (LOAD) & Overclocking
When running the CPUs at idle, the power and thermal difference are not going to be all that evident. Only once we stress each CPU can we truly see the relationship between each core's wattage rating as well as the relationship between wattage draw and CPU temperature. To stress each CPU, we ran two iterations of Prime95 with the Torture test set for maximum heat load. In each test, the system was left to run for 30 minutes before recording the results.
With each CPU running at its maximum, the benefit of the lower power BE-2350 becomes much more evident. Both the Athlon 64 X2 4000+ and Athlon 64 X2 3800+ are 65w CPUs, so their performance deltas were expectedly similar, however, the Athlon X2 BE-2350 demonstrated a 16w drop, which was close to the 20w difference that was anticipated.
When measuring the CPU temperatures during each test using ASUS Probe II, we recorded a drop of 10°C between the two "Brisbane" cores. The Athlon X2 BE-2350 and the Athlon 64 X2 3800+ "Windsor" had a 7°C difference.
Before launching into the benchmarking segment, we took a moment to see what kind of clock speed headroom the Athlon X2 BE-2350 had to offer. The first thing we did was drop our memory speed to 400MHz to ensure the memory didn't interfere with the maximum overclock and set the CPU voltage to 1.5v. Next, we pushed the CPU clock up step by step to see how high we could go.
AMD Athlon X2 BE-2350
With a stock cooler, we managed a stable CPU reference clock of 240MHz which pushed the CPU itself from 2.1GHz to 2.52GHz, an even 20% increase. Next, we put stability to the test and ran two iterations of the Prime95 Torture test for 15 minutes with no operational issues noted. Obviously we were pushing the CPU temperature a bit here, but with an aftermarket cooler we suspect the CPU has a bit more muscle to share. We should also note that the added clock speed did tack on close to 80 watts to the system draw, averaging a steady 184 Watts during load testing. With a near 20% improvement in raw performance, this nearly doubled the overall wattage draw under load.