Temperatures: Stock & Overclocked
For our next batch of tests, we recorded each processor's core temperature while running at their respective default clock speeds, and while overclocked to the same level. The "idle" temperatures were recorded after powering up the system and letting it sit at the Windows desktop for 5 minutes. The "100% load" temperatures were recorded after running the graphical Folding @ Home client for exactly 15 minutes.
Processor temperatures were monitored using the latest version of MSI's proprietary Core Center software. Please be aware that motherboards from different vendors will report temperatures differently; an Asus or Abit motherboard may report temperatures a bit higher or slightly lower than the MSI K8N Neo2 Platinum we used for testing. The temperatures reported here are only indicative of how MSI's software interprets the data coming from the Athlon 64's on-die thermal diode, and aren't necessarily 100% accurate representations of actual die temperatures...
At their default clock speeds, both processors operated with similar temperatures while at idle and under full load. The .09 micron Winchester based 3500+ was only 2oC cooler at idle and while running at 100% utilization. That 2oC difference equates to a 5.1% temperature differential while at idle and a 4.1% differential under load.
To compare temperatures while our processors were overclocked, we ran BOTH CPUs at 2541MHz, which was the maximum speed our .13 micron Newcastle based 3500+ was stable using its stock voltage. Our Winchester based CPU was capable of 2596MHz, but we wanted to have an "apple-to-apples" comparison here. While overclocked to 2541MHz the Winchester based 3500+ ran 3oC, or 7.1%, cooler than the Newcastle based CPU at idle. With both processors running under a full load, the Winchester based 3500+ again ran cooler, by a full 5oC, or 9.1%. It's also worth noting that both processors ran relatively cool by today's standards. Even while overclocked well beyond their stock speeds, and running at full load, neither CPU got hotter than 55oC. 55oC isn't exactly cool, but it's not a furnace either. We'd also like to point out that even with Winchester's increased thermal density, it was able to run cooler than a similarly clocked Newcastle using the exact same heatsink. When you shrink the size of processor's die, it has a smaller area through which it must dissipate heat, which makes them more difficult to cool. The Winchester core doesn't require any additional cooling, however. AMD's existing PIB heatsink is more than capable of keeping temperatures in check.