The maker of PSUs, Arctic Cooling, is suing AMD over the use of the Fusion name.
Arctic has been using the Fusion brand to sell its power supply units for some time now but we would be hard pressed to find someone who could confuse a power supply with a chip that integrates x86 processing cores with Radeon stream processors on the same piece of silicon.
Actually, come to think of it there are a few people who would confuse the two, but they are not the sort of people who would buy either products.
According to Heise.de, Arctic has had the trademark for ages. The company attempted to negotiate with AMD, but the fabless chipmaker hired a law firm to help with the negotiations, which was pretty much the end of things.
Arctic made its final offer for a general licence but the lawyers said the offer was unacceptable.
The royalty payment offered by AMD was actually below the cost for attorney's fees already incurred, Arctic claimed.
When HP decide to take a stab at selling Turbo Coolers, they trademarked ArcticCooler, and for time even owned arcticcooler.com, if I recall correctly. They handed it all off to Agilent, who lost interest in the product some time later. The Agilent registration on the name articcooler was canceled in 2007, per the USPTO, but they might still have common law rights.
http://www.planet3dnow.de/cgi-bin/newspub/viewnews.cgi?id=1327419131
I guess only a bunch of lawyers will profit from this case, as usual.
Oh, and AMD renamed their Fusion System Architecture into something called Heterogeneous Systems Architecture. Probably better to be on the safe side.
http://blogs.amd.com/fusion/2012/01/18/amd-fusion-system-architecture-is-now-heterogeneous-systems-architecture/