Are you using the older Google Collections and not Guava? I'd be curious to see your results with the latest Guava release 14.0.1 which includes a change to use MurmurHash3's mixK1 for hash bit smearing:<p><a href="https://code.google.com/p/guava-libraries/source/detail?r=69ad96b719d7cd3d872a948d7454f17b816a21c2&path=/guava/src/com/google/common/collect/Hashing.java" rel="nofollow">https://code.google.com/p/guava-libraries/source/detail?r=69...</a>