There were huge changes between 2.4 and 2.6, linus was considering calling it 3.0 at that time ... 2.6 has a few features that improve performance:
- Memory Mgmt
- kernel preemption
- improved threading support (NPTL)
- (( hyperthreading suppport))
I can live with 2.4, and was just wondering why DH chose not to upgrade.