This is totally unofficial... but I merged the new label code from trunk to stable a while back for someone else:
You will need to download planeshift from svn, use
the guide. Before compiling planeshift save
this to a file in the planeshift source directory called labels.patch, and on linux or mac use 'patch -p0 < labels.patch' from the console in the ps directory to automatically apply it - for windows I have no idea, ask someone else. Hopefully you won't get any failed patches, but if you do you can fix it manually or try get hold of me. Then compile it all, and download
character_set_myriad.dds from planeshift svn art, and put it in /art/effects/, then run it and enjoy

Note this is not the absolute latest from trunk, but it has the same performance. It gives speed ups only when loading areas where there are a lot of objects, or when objects arrive. I found it very good for myself, but if you are already slowed down a lot by the maps because you don't have a fast graphics card, you may not notice much difference, as some of the other testers experienced.
I also made simpler patches that just enabled the old labels to be turned completely off, but I figure if you are going to compile from source you may as well have the good stuff.
For those that are interested I recorded the load time from clicking "Join" until all labels had loaded, in hydlaa_plaza beside 150 npcs, labels always on. With two runs each, the total time for the old system was about 1:45, the new system about 1:00, and labels turned off about 0:50. So it speeds things up in certain circumstances. Bear in mind some of the lag is because of how the plaza map is made, some could be because the lighting system is unoptimized, sometimes because the server gets behind when the database is being accessed in certain ways, some is because of the sound system is a hog, some is because of map loading changes that make your computer more likely to use swap... there is no silver bullet. I think that the next version will at least partly fix some of those areas, but not all
