We have had this discussion many times. And the bottom line is that DU shows all the symptoms of bad system design.
The lack of separation on the screen render (fps) and asset loading (network/ssd streaming), being just one of many such examples.
I.e. the renderer should operate in a separate thread working only with the assets it has available, and by design it should never be affected (fps) by asset being loaded until the new voxels are finished processing and ready to be rendered. So having a slow network/storage would result in longer loading times before voxels show on the screen, but the fps should never drop while doing so.
And this problem is made even worse since DU appears to not have any occlusion culling on either streaming or rendering, meaning that everything like underground constructs, tunnels and inside of constructs etc. are always loaded and rendered while you are flying above them.