Buying a computer

I wish, when I go to a website to choose a computer I want built for me, I am NOT first steered toward "Intel or AMD?", "What Form Factor", "What 'Series' or 'Line' or Do I want a 'Workstation' or 'Desktop'": such details are of lesser importance. First, let me choose by the criteria that are important to me, say "I want 8GB of RAM", and filter out the combinations that satisfy them.