The results in the tests are all with optimisations (-O3 -march=sandybridge -mtune=intel), as mentioned in the post.<p>The exception is the Debian packaged version of zlib, because we don&#x27;t control that. That&#x27;s the reason I include stock zlib in the tests - if it had been wildly different from the system zlib, I would have looked into recompiling the Debian package with more optimisations. There were no major differences and indeed, inspecting the package further shows that it is compiled with optimisations.<p>On the Cyrus side, we used to link to the Debian zlib, so we get those optimisations. For the new code bundled in Cyrus itself, we have to enable optimisations ourselves.