I have a statcounter.com stats on my site. I was averaging 600 uniques and 3.5k impressions / day, but the most impressions I've seen in adsense was something like 1k. I have adsense on all my pages, what's the problem? Isn't 1 page load = 1 adsense impression? Today only I've scored 8k impressions, but adsense shows me ~130? I'm kinda frustrated, guess I'll just have to wait for the stats to update.
Firstly you have to wait till the end of the day for Adsense stats to be the most accurrate. Do you have Adsense ads running on all your pages? Your site stats might show pages where no Adsense ads are displayed. I'm also guessing that it might be a problem with bots accessing your site. Perhaps Statcounter doesn't exclude bots from their results or they have difficulty doing so. Adsense will not show pageloads made by bots.
Yes, I have ads on all my pages. Stats by statcounter uses javascript, as far as I know, bots don't have the ability to execute js code so therefore, they don't get logged. I also doubt that I could have 2k page impressions made by bots.
I just thought of another possibility. Do you have default ads set for your Adsense account? If you do that might be the reason. I'm sure that Adsense doesn't show the default impressions in their stats. Perhaps your site is getting a lot of default impressions.
On average, one of my site gets 100k impressions/day, but Google NEVER reports more than 20k impressions/day. Go figure.