Running the Apache web-server on the PandaBoard ES with Ubuntu 12.04 now yielded much closer results to the Intel Atom N270. The Atom N270 yielded better performance still, but it was backed by a proper SSD where as the PandaBoard ES just has a SDHC card, among other factors. The ARM power consumption is also lower than the N270 Atom.
The Dhrystone 2 performance of the dual-core Cortex-A9 setup was now ahead of the Atom N270.
The CacheBench read performance was in line with the Pentium M and Core Duo.
The other CacheBench results put the PandaBoard ES ahead of the Intel N270, but behind the other Intel CPUs.