Phabricator has the wiki, code review, and ticketing systems tightly integrated. It's a clean, fast, and free alternative to JIRA.
I didn't really have a major problem with JIRA, but we self hosted them on AWS, and the resource requirements of JIRA, Confluence, Fisheye etc. meant that we had to set up separate instances to stop them crashing all the time.
Phabricator gives us the same functionality as all the Atlassian tools I mentioned above, but on one virtual Digital Ocean $10/mo server. It is much more reliable, and has a better, much more integrated UI.
Faster too - MUCH faster. I can really tell when I go back to JIRA to log a bug and have to wait 5 to 10 seconds for a form to build itself and load.
There was no explicit performance tuning happening here, either. 1 instance of Jira talking to 1 instance of MySQL behind 1 instance of nginx on a modest VM.
I'm not doubting you, but this is a common enough complaint that I assume there's a footgun lying around that I've managed to luckily step over.