Scott, I just too a minute too look at this. I downloaded the python-attack file from your Web site. I loading all the strings and then inserted them into a dictionary. I also generated a list of 10,000 random strings and inserted them into a dictionary. The script is below. The results show that inserting the python-attack strings is about 4 times slower than inserting random strings. slothrop:~/src/python/dist/src/build> ./python ~/attack.py ~/python-attack time 0.0898009538651 size 10000 slothrop:~/src/python/dist/src/build> ./python ~/attack.py ~/simple time 0.0229719877243 size 10000 Jeremy import time def main(path): L = [l.strip() for l in open(path)] d = {} t0 = time.time() for k in L: d[k] = 1 t1 = time.time() print "time", t1 - t0 print "size", len(d) if __name__ == "__main__": import sys main(sys.argv[1])