On my system (Fedora 8 ), the new code completion very slow on start-up.
For the start-up time measurement, I start CB. At the welcome screen, I open a large project (5212 files; 1,989,931 total lines). Once all the file tabs are opened, I measure the time until the symbol browser is populated.
Using the nightly SVN, except .../src/plugins/codecompletion is pre r5770 (svn up -c5770), start-up for my project is about 40 second. The first ~25 seconds, editor is responsive, then unresponsive for the last 15, then the symbol browser is populated. Saving a source file causes an approximately three second pause, presumably while the symbols of the file are reparsed.
All of the version since 5770 through the current 5861, take approximately three minutes for the symbol table to be populated; also saving a file causes approximately the same three minute delay.
As noted, this is a Fedora 8, x86_64; gcc-4.1.2-33.x86_64, wxBase-2.8.9-1.fc8.x86_64, wxGTK-2.8.9-1.fc8.x86_64.
./configure --enable-final --disable-dependency-tracking --disable-debug \
--prefix=/usr --libdir=/usr/lib64 --with-contrib-plugins=all