IE vs Firefox browser resolution difference?

My Dolphin 7.0.3 site is rendered very differently in Firefox (3.6.12) vs IE8 (8.0.6001). IE resolution is much lower than Firefox, meaning everything appears much larger in IE (see attached).

To the best of my knowledge, both browsers are running full size (zoom = 100%), and this doesn't appear to occur on another Dolphin sites.

Is there a setting which controls this?

Thanks!

In IE... try this:

1. Click Tools.
2. Click Internet Options.
3. Click the Advanced tab.
4. Select Reset zoom level for new Windows and tabs.

Suggest clearing the browser also.

Tried couple times but didn't seem to clear up the problem =(

Curious it happens only on my Dolphin site and not others...