Pixel pipelines are very different than from shader units. The person who ever wrote that web page for EVGA isn't up to date with current tech and how it it works. Pixel pipelines date back to the Geforce 7 era on back to the Geforce 256 in 2000. This term was coined back before there was even direct x 7 let alone modern cards.
The correct info is 480 shaders or cuda cores not pixel pipelines.
In very simple terms, a pixel pipeline will normally have a single pixel shader on it working on a single pixel. (some cards like the x1900 series had 3 engines per pipeline.) It can't do anything other then shade pixels. Older cards needed separate pixel and vertex shaders. Cuda cores don't care if its a pixel or a vertex, they can do either. It's also possible for them to perform other calculations like Nvidia has for PhysX. Cuda cores can perform the same function as the old pixel pipelines but can do a great many other things.