Contextual Ads
Optimize AdSense for Faster Load Times
If you serve AdSense on your website, you may have noticed some annoying delays whilst the browser retrieves and renders the AdSense code. Search Engine Roundtable reports a thread on WebmasterWorld discussing several ways to address this issue:
Pack your ad units into a div, and give that div a fixed size in pixels (the same size as the ad unit, of course). This allows the browser to position that div and to immediately continue with the rest of the layout.