And Google has only just figured this out? I am surprised they did not do this years ago. In my opinion, Dolphin by default rather slow to load. You have to work to rip out the extra bloat that your site will definately not need. On firebug there is something call "Page Speed". This is provided by google themselves. It gives you lots of tips on how to optimise your site for speed. On one of my sites I have a page speed score of 83/100. There reaches a point where you cannot really get higher see more score without compromising your ability to make quick amendments to the code. For instance minification of the code. 100/100 would not be possible with Dolphin as it uses php which serves dynamic content and so you are penalized for not being able to leaverage bowser caching. On one of my websites I use a mixture of php and html dolphin pages to get around this and yes the pages which are pure static html get many more hits than the dynamic php pages. All food for thought.
Also yes, I agree with Magnussoft, server performance is now going to to be a major factor and so do not use where they tend to shoe horn as many user accounts on to each server. They do tend to be "nickel host"s. Ask a few questions before buying hosting. Server specifications, how many websites are hosted on the server which your account will be hosted on. These tend to give you "an idea" of what your experience is going to be like. I am sure there are lots of other question you could ask.