MSI Nightblade Z97 Model Difference?

[XtremeAero426]

What's the difference between the two of these?

http://www.newegg.com/Product/Product.aspx?Item=N82E16856167082&cm_re=nightblade-_-56-167-082-_-Product @ $400

http://www.newegg.com/Product/Product.aspx?Item=N82E16856167081&cm_re=nightblade-_-56-167-081-_-Product @ $450

 

[tiny voices]

One comes with a slim-slot DVD drive and the other does not.