It's better to use the actual JDK (i.e. the one everyone uses) rather than the implementation you get from debian apt-get due to debian's licensing hangups.<p>SBCL:<p><pre><code>  * (test)

  Evaluation took:
    45.268 seconds of real time
</code></pre>
Sun JDK<p><pre><code>  Runtime was: 51086 Milliseconds

 </code></pre>
That's less than 15%, a far, far cry from '4 times'