Well, I'm going to start by explaining that all Boss sites are unreliable. They use synthetic tests, gets specs wrong, report false info, and things of that sort.
However, they did get this one right for once. The 4690 is simply the new refresh version of the 4670, it OCs a bit better if you had the K models, but in general just runs more efficiently compared to its predecessor. In many cases it is also cheaper.
Everyone used to recommend the 4670, but this was because the 4690 wasnt released yet.