*GUI = graphical user interface
So we have arrived to the most important part of this 7 days with Firefox series: GUI and benchmarks.
The most impressive update of Firefox or at least the most visible is the graphic user interface updates. Everything about it is up-to-date with the latest trends in business and most of them established by Opera interface designers. This is not a surprise, Chrome, Firefox and even Safari have inspired over time from Opera’s features: tabs is the most common one. But what really strikes me is the amount of similarity between the new Firefox and Opera when it comes to GUI.
I know for a fact that Firefox’s 4 interface was designed with the help of the open and supporting community of Mozilla and I know how important over time this community was for the browser manufacturer, but a little innovation when it comes to GUI would certainly help on the long term. Even so the browser looks modern and ready to tackle its opponents in the Windows OS environment.

Another Opera inspiration GUI feature is the alert view, as seen in the picture next. This looks pretty good and surely we will see something similar on Chrome in the near future.
Also a big point on the Mozilla’s designers’ agenda was the reduction of the space occupied by the menu and location bar. In fact this is a concern for all the browsers, mainly because nowadays we use mostly wide screens which don’t have as much image height as the normal 4:3 ones. You can see in the gallery below a comparison between Firefox, Opera, Chrome and IE when it comes to vertical space occupied by the browser window.
Having said this it is time to see the benchmark results. I have run 4 benchmarks, most of them analyze the speed of the JavaScript engine renderer:
- SunSpider JavaScript Benchmark
- Google V8 Benchmark Suite
- Kraken JavaScript Benchmark
- Peacekeeper Benchmark
So we have 4 competitors (in alphabetical order): Chrome 10 dev, Firefox 4 beta 10, Internet Explorer 9 beta and Opera 11.
SunSpider JavaScript Benchmark
This test measured the speed of rendering JavaScript code. Here the lower result is the better one. The values are measured in ms, 1000 ms is equivalent to 1 sec.

The clear winner of this test is Opera, with Firefox coming second followed very closely by Chrome. What is not that clear is the fact that Chrome loses this battle to Firefox’s new JavaScript engine, this is a first in history: from its 0.1 version till now, Chrome’s JavaScript engine was always faster that Firefox’s one.
Google V8 Benchmark Suite
This is another JavaScript render test and it is made by Google. The higher value is better.

Well a surprise or not the winner is Chrome 10, followed by Firefox and Opera. Internet Explorer wins another last position.
Kraken JavaScript Benchmark
This is the last JavaScript test of the three, it is mostly designed after SunSpider benchmark and is made by Mozilla. The lower value is better, and the values are in ms.

Internet Explorer 9 has crashed repeatedly so it is not included in this chart. Chrome wins this one and surprisingly Opera loses. This is a surprise mainly because Kraken Benchmark is mostly based on SunSpider Benchmark and you would expect the results to be similar.
Peacekeeper Benchmark
Peacekeeper is a benchmark made by Futuremark, a company very well known for its video cards benchmarks. Here the higher value is better.

The winner in this benchmark is Chrome 10.
All the test were made on my PC which runs a 64bits Windows 7. The results differ from PC to PC, but the proportions should be maintained.
Conclusions
In the beginning of this series I have said that this new version of Firefox is mainly an evolution, but I realize now that this is only one part of the truth. I am a Chrome user and for me Firefox 3.6 was a pain in the back with its slow start and high memory freeze, but with this new version Firefox grew. They really invested some time in making this new version of Firefox as good as they could and guess what? They really did it: for Firefox’s users this 4th edition is really a revolution!