In my quest to build the fastest website possible, I stay busier than a Colorado Taco Bell employee working the late shift. I have several methods of testing website speed; one of the automated tests I like to use is Google PageSpeed Insights.
In following their recommended techniques, websites will get a lower grade for using an external style sheet (if the style sheet is small). Therefore, I started testing inline styles as opposed to an external style sheet. I realize there are many different variables in determining the speed and my test are not the most scientific, but if you look at “exhibit A”, the page with the inline styles is over 100 milliseconds slower than “exhibit B” which is using an external style sheet. However, by using an external style sheet, the site loads faster in the real world, so I believe I am going to stay with the external file on my website for now.
I am using Typekit for my web fonts and that also brings down the score, but I am thinking it is still faster than using images, not to mention the time it takes to develop and optimize the images. I believe speed is king and it will always be a factor on the web. With the percentage of mobile web surfers climbing it will be even more of a factor. In the end, using automated tools for testing is good, but using common sense and real world test will always be a better solution.