Back when I started writing Java software in 1997, the Java Virtual Machine was slow. It was so slow that for years, many developers abandoned all hope of using the language for "serious" work once it became clear how much slower it was than C and C++. Eleven years of Moore's Law compounding, and countless JVM optimizations later, Java is so fast today that relative speed is rarely even considered when developing client and server applications.
Put a V8 in Your Browser
How fast is Chrome's V8 engine? We can get an idea by running some benchmarks.
The chart below shows the results of running Google's V8 Benchmark Suite (bigger bars mean faster execution):
As you can see, Chrome leaves both Firefox 3 and IE 7 in the dust, at least according to this benchmark. Another popular benchmark is SunSpider, where the results are qualitiatively similar; Chrome's execution time surpasses that of IE 7 by over two orders of magnitude.
My system consisted of an Ubuntu Linux machine running a clean install of Windows XP on Sun's excellent virtualization product, VirtualBox. Your mileage may vary. Note: it's important to disable Internet Explorer's warning prompt that reads "This page contains a script which is taking an unusually long time to finish. To end this script now, click Cancel." (the presence of which is telling in itself).This can be done by following the instructions here.