Microsoft on Wednesday released the seventh platform preview of its upcoming web browser Internet Explorer 9 (download link). Comparatively less stable than beta builds, platform previews are aimed at acquainting developers with new features and gathering valuable feedback.

According to Dean Hachamovitch, Microsoft’s corporate vice president of Internet Explorer, who wrote a copious blog post to discuss the latest platform preview release, improving real world site performance, and not “subsystem microbenchmarks,” remains the real focus of company’s development efforts.

This release mainly revolves around improvements to the browser’s JavaScript engine, codenamed Chakra, which has been heavily fine-tuned “for more of the patterns we’ve found in real world sites.” Apparently, all this optimization gives IE9 an edge over the latest versions of rival browsers when it comes to real sites.

Even though he was in his familiar anti-benchmark mood, he did take a slight break from his treatise on the current obsession with benchmark tests to tout IE 9 Platform Preview 7’s performance in the SunSpider JavaScript benchmark.

But he soon clarified: “We’ve been consistent in our point of view that these tests are at best not very useful, and at worst misleading. Even with the most recent results in the chart above, our motivations and our point of view remain unchanged.”

“We’ve focused on improving real world site performance. We’ve made progress on some microbenchmarks as a side effect. Focusing on another subsystem microbenchmark is not very useful.”