The number of HTTP requests and combined size of the requests has the potential to negatively impact page performance. The table below shows how the core of each framework performed. In all cases the CSS files can, and should, be combined and minimized (whitespace and comments removed) but these comparisons were done with the code as provided by each vendor.
The page impact of each framework looks pretty good. In a real-world scenario, the files would be stripped of unused code, combined and minified. Given those circumstances, none of the three frameworks reviewed should have a negative impact on page performance.
|Framework||HTTP Requests||Size in kilobytes|
|960 Grid System||3||15.6|
|Source: Yahoo! YSlow for Firebug|