See http://bugs.kde.org/show_bug.cgi?id=78978, kdevelop consumes a huge amount of system memory opening certain files, hogging the system resources for about 30-40 seconds on my system. I could confirm this bug in KDevelop 3.3.2 and 3.3.4. There's a small patch in the upstream bug report that fixes this.
Can you confirm this bug for version 3.3.5?
Please ignore comment #1.
This is not a memory leak. The memory is freed again after the system is busy for about half a minute. But it keeps you from doing anything for this time, whenever you open certain .c files. Not only when you import a project. It is extremely annoying. Please apply this patch and make a new release.
Asked stabilisation of 3.3.5, that will fix the problem.