Navigator Gold 3.0 appears to cause a overall diminished performance when it is an active background application. Test were performed on a Performa 6300. Testing was done using MacBench 3.0 . MacBench profiles popular software programs such as Adobe Photoshop, Word 6.0 and QuarkXpress among a variety of others and applies these profiles to the various subsystems being tested. See this description of what MacBench tests and how.
Longer bars equals faster performance.