Why is the Enterprise version of Windows 8 a smaller download?

From my MSDN subscriber account, I see that the Windows 8 Enterprise edition is a smaller sized download than the regular edition (3329 MB vs 3416 MB):

I looked up Wikipedia to double check - the Enterprise edition does contain many more features. How could the smaller ISO size be explained, then?

Solution 1:

The Windows 8 Enterprise edition does not contain the media center and gaming functionality that is included in the Windows 8 Pro edition, which is strictly a superset of the normal "Windows 8". Additionally, the Windows 8 ISO contains multiple products, as it states; both the home and pro editions. Which edition is activated depends on the key you enter.

Solution 2:

First of all, a ~3% size change is probably not significant to draw any meaningful conclusions.

However, based on the Wikipedia page you linked, the enterprise edition doesn't support Windows Media Center, whereas you can add it in the regular edition. It would not surprise me if omissions of various media stuff like this would make the enterprise image slightly smaller.