A Look At Ubuntu 10.04 To Ubuntu 18.04 Linux Performance
The Himeno pressure solver is running faster on newer Ubuntu releases, except for the i7-990X taking a hit with Ubuntu 18.04.
The 7-Zip compression performance has improved a bit with newer Ubuntu releases. 7-Zip though is another test showing how the i7-990X has shockingly regressed heavily going from 12.04 LTS to 14.04 LTS and still isn't close to its original performance during the Lucid Lynx and Precise Pangolin era.
The time it takes to build the Linux kernel (Linux 4.13 for this test profile) has mostly been maintained the same with the i7-4960X and i5-2500K, but the i7-990X does regress hard on Ubuntu 14.04 LTS -- a theme that seems to be for this older Intel system slowing down a lot in the CPU tests.
The C-Ray ray-tracing performance on the i7-4960X box saw a nice boost in performance from 12.04 to 14.04 LTS while the i7-990X continues getting slower...
In the case of AOBench, at least here the i7-990X system didn't regress as badly from 12.04 to 14.04 and has been improving since. AOBench is another test case showing how GCC optimizations have matured over time.