having only one unit against multiple units

I have read many posts about this topic but cannot come to a conclusion,
anyone received higher CPC when using only one adunit other than 2 or 3.
what about the CTR in that case.
i feel CTR will decrease and CPC may increase as all high paying ads have to be shown within a single unit what do you feel.

 

I've not tested it, but personally, I'd rather have more ads in front of each pair of eyes - more chances somebody will see something that interests them and click on it.

If it means sometimes lower payouts, so be it - I'd rather have that click than none at all.

 

Test it yourself. These things are niche and site dependent.

 

Less is More

 

I find that on pages with hard to find out-bound clicks, that one ad-unit will be clicked on in decent CTR rates, even if it's below the fold.