The beta period for Visual Studio 2010 is being extended by adding another interim checkpoint release, a Release Candidate with a broad “Go Live” license, which will be publicly available in the February 2010 timeframe.

S. Somasegar, Vice President of Developer Division, wrote in his blog post, “You have also given us feedback around performance issues, specifically in a few key scenarios including virtual memory usage. As you may have seen, we significantly improved performance between Beta 1 and Beta 2. Based on what we’ve heard, we clearly needed to do more work. Over the last couple of months, our engineering team has been doing a push to improve performance. We have made significant progress in this space since Beta 2.”

The beta extension means that the launch of Visual Studio 2010 and .NET Framework 4 has been moved back a few weeks into early April.