Not only did he not give the Hotspot time to warm up but we have no idea what the overhead of the Dropwizard stack is (i.e., if its heavily IO dependent that&#x27;s going to obviously shift things), what Application&lt;T&gt; looks like, what the emitted code is. If it&#x27;s anything like Clj, the overhead of the package runtime is not insignificant. The native GC logging is way better than using log4j (which is great for logging, but abymsal in situations like this for obvious reasons...). He&#x27;s on OSX, if he wanted to conduct this with even the slightest bit of rigor he would have used Dtrace and probed a few application runs with appropriately placed probes. Like it&#x27;s already been mentioned, he should be using whatever the JDK (or ideally JMH, IME) gives him to bench rather than that log4j derivative, because that could potentially introduce disk seek variance between the two GCs (i.e one could be simply buffering, then capturing stdout&#x27;s FD, and flushing -- rather than having 60 very significant potential &#x27;get FD, (potentially block until you can acquire a mutex on it; then potentially wait to seek out) , write, flush&#x2F;sync&#x27; while the other one might have just done it once (as I have no idea about the the library he&#x27;s using to log, nor have I used an OS X file system in production (unless it uses UFS1 in which case I when I was 13 or 14 for a bit). He&#x27;s writing to a tty so that&#x27;s probably not going to impact performance too much I&#x27;d imagine, but if you&#x27;ve real-time cat&#x27;d a 200 meg file out to a tty, you&#x27;ll see that the benchmark is actually output to the screen rather than the throughput of the disk (again, not sure why, probably has a lot to do with the X11&#x2F;Xorg frame-buffer being slammed and&#x2F;or the bloat of the term you&#x27;re using (you&#x27;d absolutely see variance between something minimal like xterm + sh, vs gnome-terminal + zsh)). Anyways, yeah, he should have read some Oracle docs to minimize the number of independent variables between his two cases to make this even moderately definitive. (Also I&#x27;m baffled why he even put in any IO what so ever if the whole point was to bench the 4 different modes of GC...).<p>Anyways, instead of tearing apart his post by pointing out the complete lack of rigor and experimental design foresight he exhibited, something fun to do is to take the Sun JVM, IBM J9, OpenJDK, Graal (or something along the lines of that) and Zulu (if you can scare up a Zulu license you&#x27;re in for a pretty interesting treat). It&#x27;s amazing how one IL can yield so many different performance results.