TSS/360 duplex
somebody recently quoted a soviet press article about a us/soviet track meet .... where the soviets came in 2nd and US came in next to last.
In the early 70s there was TSS/360 duplex benchmark showing it ran 3.8 times faster than same TSS/360 on single process. Somebody wrote it up as TSS/360 having far superior multiprocessor support (much superior than any other operating system in handling multiprocessors ... i.e. any other system would at most get twice the thruput).
It turns out that the both TSS/360 benchmarks actually had much inferior thruput compared to cp67. The scenario was that single processor 360/67 had 1mbyte storage and TSS/360 kernel was so bloated that only small amount was left for application execution (and single process benchmark was page thrashing). The two-processor 360/67 had 2mbytes storage .... which was enough to have more efficient application (after what was taken by the bloated tss/360 kernel) ... getting nearly four times the thruput.