The only problem [Nvidia has] is that at some point your eyes don't get any better - Bob Colwell, former chief architect, Intel
The patents cover so-called "Predictive Snooping of Cache Memory for Master Initiated Accesses".
Opti alleges that Nvidia has infringed its patents by making and selling products based on predictive snooping and the low pin count interface specification.
It also alleges that it has induced others to contribute to the infringement of its patents, by which it presumably means Nvidia's partners.
The patents in question are here, here, here, here, and here.
The last two refer to an Opti patent for a compact ISA bus interface. ยต