The Linux Kernel Power Problems On Older Desktop Hardware

When running the Apache web-server on this old Intel "Northwood C" processor, the 2.6.32/2.6.33 kernels have slightly higher power consumption than the newer kernel builds. It is hard to detect any 2.6.35/2.6.38 power regressions with this hardware when the CPU is busy.

The Apache performance also goes up with the Linux 2.6.34 kernel. The number of requests per second being handled goes up by approximately 90% with the 2.6.34+ kernels. At first it was thought that possibly the 32-bit pre-2.6.34 kernels were being built without SMP (Symmetric Multi-Processing) support based on these differences, but in fact SMP was still there with the 2.6.32/2.6.33 vanilla kernel builds.