IE7 RC1 vs. Firefox2 RC1

IE7 RC1 vs. Firefox2 RC1

Summary: Internet Explorer version 7 RC1 and Firefox version 2 RC1 are now out so I thought it would be a good time to do some simple side-by-side comparisons. The "RC" stands for Release Candidate, meaning that these are the near-final versions. And the winner is...

TOPICS: Browser

Internet Explorer version 7 RC1 and Firefox version 2 RC1 are now out so I thought it would be a good time to do some simple side-by-side comparisons. The "RC" stands for Release Candidate, meaning that these are the near-final versions.

Unfortunately IE7 wouldn't install on my primary computer so I had to compare them on a slower laptop.Firefox 2 appears to have a slight but unmistakable edge It's an IBM Thinkpad T42 with a 1.7Ghz Pentium M processor and 2GB of memory, running Windows XP SP2.

First I tried the (in)famous Acid2 test, a page "written to help browser vendors ensure proper support for web standards". Here's the output drawn by IE7RC1:


And here's the output drawn by FF2RC1:


Neither one gets it quite right but Firefox looks closer. If you want to see what these are supposed to look like, click here.

Advantage: Firefox 2 

Next I ran a test from that simply measures how long it takes the browser to render a large (>800K) table. Times varied considerably (from 4.186 to 5.788 seconds) so I ran the test 5 times and averaged the lowest 3. The results:

  • IE7RC1:  4.346 seconds
  • F2RC1:   4.289 seconds 

Given the variability of the times we'll call that a statistical tie.

Advantage: None 

JavaScript performance is especially important for today's Ajax applications. So for the final test I ran the JavaScript Speed Test at This measures 7 aspects of the browser's JavaScript engine. I ran the test 3 times and took the average for each of the 7 tests (all times in seconds):

  1. IE: 1.002, FF: 1.642 (Counting to 10000)
  2. IE: 4.743, FF: 2.086 (Open pop-ups)
  3. IE: 0.497, FF: 0.554 (Replace images)
  4. IE: 1.325, FF: 0.691 (Text manipulations)
  5. IE: 1.195, FF: 0.183 (Set tables)
  6. IE: 1.445, FF: 1.946 (Put layers into place)
  7. IE: 1.786, FF: 0.921 (Calculate x-mas)

Total: IE: 11.993, FF: 8.024

Advantage: Firefox 2

In conclusion, picking a browser involves more than just running a few benchmarks and going with the fastest one. Your decision will be influenced by many factors such as security, compatibility with the sites you use, support for your platform, and extras like bookmarks and web feeds. All we can say for sure is that on this computer, for these tests, Firefox 2 appears to have a slight but unmistakable edge over its closed source rival from Redmond.

I didn't look at other contenders like Opera and Safari here. But regardless of which browser you use, you are the real winner in this battle as the browser superpowers try to outdo one another.

Topic: Browser

Ed Burnette

About Ed Burnette

Ed Burnette is a software industry veteran with more than 25 years of experience as a programmer, author, and speaker. He has written numerous technical articles and books, most recently "Hello, Android: Introducing Google's Mobile Development Platform" from the Pragmatic Programmers.

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  • Someone is missing from the test!

    It would be nice if you included all the major browsers for Windows in these tests, to wit Opera 9. while I don't use it much here myself as I'm deeply involved in torturing MSIE 7, I think it would compare quite favorably to the others if not superior in some of the speed tests given my experience on many sites with it.
    • Opera

      I knew someone would take me to task for not trying Opera. :) I didn't have time for this article but the figures I've seen on other sites indicate it would do very well speed-wise and on Acid2.
      Ed Burnette
  • Memory Use

    The memory use of Firefox 2 RC1 also compares favorably to IE 7 RC1 (and Opera 9.02) <>
  • Hard to get them all

    ... except by inference. IE7 is Microsoft-only, and the KHTML engine is pretty much only for the Unices.

    I suppose you could compare them to FF and Opera as calibration points.
    Yagotta B. Kidding
  • I tried the acid test Konqueror (KHTML) and Opera

    Both beat the pants off IE and Firefox. Neither was perfect, but Konqueror was just a slight bit more accurate. The nose and mouth were in alignment in both, but in Konqueror the eyes were just slightly askew to the right. They were further to the right in Opera. There was also a shaded line in Opera that starts to the left of the left eye and then goes straight across the head just over the eyes. Konqueror has the shaded line too, but it's thinner and only goes above they eyes. And the tops of the heads are just a wee bit askew in both.
    Michael Kelly
    • I tested with the nightly build of FF

      Just 2 lines are askew with Gecko/20061001 Minefield/3.0a1. There is visible improvement.

      Its a almost there.

      By contrast IE 7RC1 appears to render it the same as IE 6. No improvement.
      Edward Meyers
  • Hmmm... Why didn't you test SVG rendering

    Oh wait! MS IE is the only modern browser that does not have naitive SVG rendering capabilities. Microsoft being Microsoft is still stuck on VML instead of using the standard, SVG.
    Edward Meyers