Why would they be any different?
Stupidity got us into this mess - why can't it get us out?
- Will Rogers
because, laterally, they're twice as thick
Hard to tell. Going by weight the straight DT is 43% heavier than the X-Ray, This probably means that the DT has a bigger cross section, and cross section is important for stiffness. But Sapim do go on about special alloy treatment and high tensile. Maybe their stainless is so much tougher than the DT stainless that they actually can make a spoke that's both lighter AND stronger. Seems improbable though, so my guess goes to straight DTs making a stiffer wheel.