Thirteen-year-old Opera has been the perennial underdog in the browser wars, but the Opera 10 alpha brings some unexpected fire power to the battlefield.

Unlike Google Chrome, Firefox 3 or any other browser on the market, except for Safari 4 Developer Preview, Opera 10 will comply fully with the Acid3 test, according to the Norwegian company.

Set to be made available on Thursday for public testing, Opera 10 is powered by an update to its proprietary rendering engine. Presto 2.2 is supposed to be 30 percent faster than Presto 2.1, the engine driving Opera 9.5. Presto 2.2 will be the basis for future versions of Opera's mobile browsers, as well as the desktop editions, the company said.

Image credits: Seth Rosenblatt, CNET Download.com

In addition to the engine improvements, Opera 10 apparently scores 100 out of 100 on the Acid3 testing website. The Web Standards Project created the Acid tests to check a range of linking and rendering abilities in browsers, to encourage a standard baseline for coding. Theoretically, sticking to the test rules should ensure that websites can be seen properly on any browser, while reducing development costs.

For comparison, Firefox 3.0.4 scores 71 out of 100, while Firefox 3.1 Beta 1 scores 89 out of 100. Google Chrome 0.4 earns 79 out of 100, while Internet Explorer 7 struggles at 14 out of 100.