When you say the module 'seems to work fine', do you mean the module itself, or this script specifically? How many lines in lan.txt? Given the name 'lan.txt', are all the sites you are hitting accessible via fairly high bandwidth links? If the sites you are hitting are generally responding pretty quickly, and you have lots (more than say, 300) of sites in your file, it is not surprising that the CPU pegs. Could you be more specific about draining memory, ie, how much how fast?