For some results that are more interesting than the recent RHEL / Oracle / CentOS / Scientific Linux comparison, here are some benchmarks pitting Red Hat Enterprise Linux 6.2 against a development snapshot of Ubuntu 12.04 LTS on three different systems.
On the same three systems as the earlier article, Ubuntu 12.04 LTS x86_64 was benchmarked against Red Hat Enterprise Linux 6.2 x86_64. The three systems were the same and included Intel Core i7 3960X Sandy Bridge Extreme Edition, dual AMD Opteron 2384 quad-core Shanghai, and Intel Core i5 2520M CPUs.
Red Hat Enterprise Linux 6.2 is using its patched Linux 2.6.32 kernel with various back-ports, GNOME 2.28.2, X.Org Server 1.10.4, Mesa 7.11, and GCC 4.4.6. Ubuntu 12.04 LTS "Precise Pangolin" meanwhile is set to ship this April with the Linux 3.2 kernel, Unity 5.4.0, X.Org Server 1.11.3, Mesa 8.0, and GCC 4.6. For this comparison, the main differences to note is the Linux 2.6.32 kernel and GCC 4.4.6 compiler with RHEL 6.2 while Ubuntu 12.04 LTS is with the Linux 3.2 kernel and GCC 4.6. The Ubuntu 12.04 LTS snapshot was from 19 February.
Across all three systems and with both the Ubuntu and Red Hat Enterprise Linux installations, the stock packages / settings were maintained.