SGI, whose widgetry is based on Intel, claims that ATI's line of Radeon graphics processors infringes its US patent no. 6,650,327 entitled "Display System Having Floating Point Rasterization and Floating Point Framebuffering." It wants treble damages and an injunction.

According to SGI CEO Dennis McKenna, "The company's technology covered by the '327 patent is an important resource in achieving enhanced graphics processing demanded by today's computer systems. SGI has licensed this technology to ATI's major competitors [read Nvidia] and, as I have previously been stating publicly, SGI intends to aggressively protect and enforce its IP. This is the first visible step in that process."

Radeon products, made since 2000, are used in desktops, laptops, workstations and servers.

The SGI patent was filed in June 1998 and issued in late 2003.