Be careful, this is one of the most intense and bitter debates in the audio world.
Yes, people fail 100% of the time to consistenly demonstrate that they can hear audible differences between cables.
Yes, these tests are not conclusive or all encompassing in determining that these differences don't exist, and are flawed in many ways.

I think the bigger point here is what is the most effective allocation of your financial resources. Pretty much everyone I know will put cables dead last when building a system...that should tell you something.