Trying to set render distance >16 results in unresponsive client

When I try to set the render distance higher than 16, Minecraft becomes unresponsive, and maxes a single CPU thread. After a minute or so, it will update, but then the slider will start jumping around. Setting 32 in ~/minecraft/options.txt does cause it to SAY 32 in the video settings, but it appears more like 16 when viewed from the build limit.