Why are mavic aksiums so slow?

[biker77]

as training/general riding wheels the aksiums are fine. Hubs roll well it is just going downhill there is so much drag that it is noticeable.

maybe the ovals have the same aerodynamics or are heavier? I am not sold on bladed spokes and think that they may also be part of the problem. It looks like your wheels have the same lacing:

http://www.performancebike.com/bikes/Product_10052_10551_1116696_-1_1641513_1641008_1641518