My site has the same problem. With adblock enabled, pages on my site render in about 800ms. When the adsense ads show it takes 2.5 seconds.

I recently switched from straight up adsense code to Google DFP adserver. That allows asynchronous loading of adsense ads. That means the "onload" event fires before the ads finished loading. Since some javascript happens onload on my site, it helps with the user experience.

As far as penalties go, Google has said they don't specifically penalize sites that aren't in the bottom couple percent. That means that unless your load times are 10 seconds, you aren't getting whacked by a specific algorithmic penalty.

Its also clear that Google's algorithms take user satisfaction into account, and that user satisfaction can be affected by slow load times. Based on reports from others here, getting your site to load in 3 seconds or less is where you need to be to make users happy enough to not negatively influence your rankings.

It is really unfortunate that Adsense is so slow, but as long as your load times are under 3 seconds, you should be fine from an SEO perspective.

Ads tack on 3-5 seconds to our page loading time usually. I haven't noticed a problem. Webmaster Tools says 88% of sites are faster than us, but we rank very high so I don't think it's impacted us SEO wise. Then again, I have around 2.8 million organic links pointing to the site.

Also, we use asynchronous code for serving ads as well. So users will get the page content in like 2-3 seconds usually. Thing is Google's site speed algo still counts the time the ads take to load, even when the page is otherwise completely usable.

Another site I host on the same server has no ads, is faster than 80% of sites and doesn't rank anywhere near as well.

If the ad code is Javascript it should matter that much. You content load before the ad.

Clarence, the measured speed in Webmaster Tools labs is over 4 seconds, which clearly includes the ads (page load time without is about 600ms), so I think setzer is right that it is counted by the algo.

deadsea, Thanks for the Google DFP tip. I did not try it because I though Adsense was now async anyway, but if it can make a difference, I will try it.

Is the WMT speed tab measure still working ?

I just read the September Adsense Newsletter. Most of it is about how important it is that sites load fast ... sigh.

Is the WMT speed tab measure still working ?

Mine isn't. It's stuck on August 10. There's a link to a Page Speed Tool, but I don't find that particularly useful when what I want is a quick overview of any pages that need speeding up.

I do a lot of web surfing every day. I always watch the status bar. What do I see the most?
I see -
"Waiting for ads.doubleclick" over and over - frequently, for MINUTES at a time.

No "doubleclick" for me, thank you very much.

I think you would be surprised how slow some of these external requests can be... I use tools.pingdom.com. In one recent case we found a specific publisher network taking on average of 4 seconds just waiting, and in many cases it got up to 5 and even 9 cases.