qTranslate’s lack of performance has been a recurrent topic in Internet. q-X has improved a few things, but there is still a lot to do.
On other hand, one has to understand that this plugin has a lot work to do indeed, mostly it is much bigger job than any other plugin. It is ok that it takes more time than any other plugin, important thing is that the total time would stay reasonable.
qTranslate X seems to be the problem
It would help if you provide more information. Which version? Did you try to compare one version to another in exactly the same environment? What about the latest beta from GitHub? Is it worse of better? Screenshots of your analysis would be good to take a look at. Which specific queries? Search results vs single page, etc.?