Short bio: Computer Scientist, FOSS supporter (read more)
Tux Machines (TM)-specific
Though as the Phoronix Test Suite stack is presently bisecting and analyzing the kernel during the period in question (Linux 2.6.37 to 2.6.38), this article is being published now and hopefully on Easter Sunday or Monday the actual offending commit will be known along with much more information. This bug has also now been confirmed independent of Phoronix by at least six separate parties that I'm aware of, with reports of Natty either consuming excessive power or a very significant increase in heat output compared to Ubuntu 10.10. These independent reports have occurred on a range of hardware -- including desktops. There is also at least one bug report on the matter for Ubuntu 11.04.
Ubuntu 11.04 "Natty Narwhal" is set to be released on Thursday and while there are a number of new features to talk about in this latest release, the Phoronix Test Suite software has been busy analyzing the performance of this latest release. There is open-source graphics driver improvements leading to some performance improvements (such as Radeon KMS page-flipping), the famous ~200 line Linux kernel patch to improve responsiveness, and various other enhancements that catch our fancy in Ubuntu 11.04. However, one area where there is a frightening regression in Ubuntu 11.04 is with its power consumption. For mobile devices in many workloads, Ubuntu 11.04 is consuming noticeably more power than in any of the past Ubuntu Linux releases. Sadly, no one seems to have noticed in time since continuous integration testing on Linux seems to happen so haphazardly right now.