CSS: Is inline styling slower?

Question

Which renders faster?

// Just HTML
<div id="holder">
    <div style="float:left;">test1</div>
    <div style="float:left;">test2</div>
    <div style="float:left;">test3</div>
</div>

OR

// CSS
#holder div{
    float:left;
}

// HTML
<div id="holder">
    <div>test1</div>
    <div>test2</div>
    <div>test3</div>
</div>

Answer 1

In terms of actually displaying content, the speed differences between the two sections of code is negligible. Different browsers most likely have different implementations for rendering a webpage so the minute speed boost you get with one browser won't necessarily be reflected in another.

Now in terms of load times, it's a different story. Yes, inline styles are technically faster than an external stylesheet because you are making one less request on top of the page but using an external stylesheet is much preferred for code maintainability. It's only when you're loading multiple stylesheets that performance starts to become an issue since each time you refer to an new stylesheet the browser must submit another request. The solution? Simply concatenate stylesheets together into one.