Does AdSense dislike banner ads?

EPC drops drastically when banner ads on page

[btas2]

Does anyone know for sure (not that anyone knows anything for sure about AdSense) if EPC depends on the presence of competing banner ads on a page?

The reason I ask is that a placed a set of rotating banner ads (from CJ) on a page a couple of days ago. These are standard graphic banners (468x60) from affiliates, so they are OK to run with Adsense accoring the the rules.

There were no other changes to the page at all. Layout is identical, except for a centered banner in the header. Impressions are normal, AdSense clickthrough rates are normal, but EPC has dropped by at least factor of two. In fact the EPC for the two days the banner ads have been there is the lowest EPC I've ever seen on that page.

I'll probably pull the banners tomorrow if today keeps looking as bad as it does right now. Just wondering if others have seen this effect or if I'm joing the paranoid club?

[alika]

Not as far as I can tell. We run adsense with banners since 2003. Banners from banner ad networks, CJ, our own products, and there seems to be no correlation