Opera Software ASA Thursday launched a preview of its next browser, Opera 10, that aces the Acid3 Web standards test, a mark that most browser makers have pursued without success.

Opera 10 also contains the Norwegian browser maker's newest rendering engine -- dubbed Presto 2.2 -- that the company plans to use as the foundation for all future builds of its desktop and mobile products. Opera claimed that the new engine boosts rendering speeds by up to 30% over its predecessor, Presto 2.1, which debuted last June as part of Opera 9.5. Other additions include an auto-update tool and a spell-checker that works as users type in the browser window.

But Opera also touted its perfect Acid3 score Thursday. "Opera has fine-tuned its standards support and, as a result, Opera 10 alpha achieves an Acid3 100/100 Test score," the company said in a statement Thursday.

Earlier this year, Opera and the WebKit project, the open-source initiative that produces the engine that powers both Apple Inc.'s Safari and Google Inc.'s Chrome, duked it out over Acid3 bragging rights.

On March 26, Opera claimed that it had created a "reference build," a version used internally for testing and development, of its browser that scored 100 on Acid3, a test suite produced by the Web Standards Project that checks how closely a browser follows certain standards, particularly specifications for Web 2.0 applications.

Later that same day, WebKit developers countered with similar claims, and backed them up with in-progress builds to prove them. More recently, WebKit programmers said that after more work, their engine was "the first browser to fully pass Acid3" by not only scoring a perfect 100, but also meeting Acid3's "smooth animation" requirement.

Computerworld's tests confirmed that the alpha of Opera 10 scored 100 on Acid3, and that only WebKit matched it. Acid3 was run on either an iMac powered by Mac OS X 10.5, or a PC running Windows XP SP3.

The results were:

-- Opera 10, alpha (XP) -- 100

-- WebKit r38860 (Mac) -- 100

-- Firefox 3.1, nightly build (XP) -- 92

-- Firefox 3.1, Beta 1 (XP) -- 88

-- Opera 9.6.2 (XP) -- 85

-- Chrome 0.4.154.31 (XP) -- 79

-- Safari 3.2.1 (XP/Mac) -- 75

-- Firefox 3.0.4 (XP) -- 71

-- Firefox 2.0.018 (XP) -- 52

-- IE8 Beta 2 (XP) -- 21

-- IE7 (XP) -- 12

The Opera 10 preview can be downloaded from the company's site in versions for Windows, Mac OS X and Linux.

For more enterprise computing news, visit Computerworld. Story copyright Computerworld, Inc.