This article can not be trusted. The version of FreeBSD they use in the test is in 'debug mode'. The speed of every critical system is impacted while debug symbols are enabled. The fact the author fails to mention this critical fact casts doubt over the veracity of the entire article.
MALLOC_PRODUCTION was set and INVARIANTS and WITNESS were disabled on the 10th, a full week before RC1 was built. Wouldn't be much of a release candidate if it wasn't built using release flags, would it?
Most of the benchmarks look to be more about compiler version and flags than OS, though. Lots of CPU-bound tasks which barely even touch the kernel, woopee. The Stream numbers were quite interesting, perhaps indicating that particularly microbenchmark loves NUMA awareness, which is hardly surprising but perhaps not entirely representative of many real world workloads.
The benchmarks might have been more exciting if they measured scaling to multiple CPUs, given that's where most of the advances in modern OS's are going. Some Apache/MySQL/PgSQL/Varnish/Squid numbers might have been nice too, given that server tasks are a major focus of both OS's.
What exactly do you mean by "debug mode"?
FreeBSD has some standard debugging features during development (-current) and beta stages like WITNESS etc, but those have been disabled for 8-RC1 and later.
