Xara pixelates shadows at 6000 x 6000 exported tiff at 96 dpi?

Why is this happening?, attached is a 100% view of a circle that is 6000 x 6000 pixels,
everything else exports clearly, only the shadow pixelates, what can i do to stop
the shadows from pixelating, any suggestions?
this happens with everything i try to export at a large size, why don't the shadows remain clean
like the rest of the graphic?

jnerf

Did you use the shadow tool? perhaps try creating a vector shape and use the feathering and transparency tools and see if that exports any cleaner.

its the the blur/feathering shadow edges that is causing the pixelation I think

with the shadow tool, if you zoom in and adjust the top slider of the shadow tool profile over to the far left you will see the stepping more clearly

remember that feathering/bluring is a bitmap effect as it is achieved at pixel level in Xara

maybe making the shadow seperate at a high resolution might help

tried Frances' sugesstion and the stepping seems less obvious at the size