I have been running Ubuntu 12.04 LTS on my Dell XPS M1330 for a couple days and the system gets really not. The fan does work but doesn't seem like it runs long enough, often enough, or fast enough. I have seen a few posts about it but most of the issues are related to the nVidia GPU set which has had heat problems since release (I use to repair Dell laptops for a living). My machine does NOT have the nvidia GPU. I am also running a SSD in the machine so that by itself should help the machine run cooler. The BIOS is fully up to date and I do not have this issue running Windows 7, 8, or 8.1.

Note: In the time it took me to compose this post, the palm-rest of the laptop has gotten noticeably warm.