Just a little optimization, nothing more. Primarily data.zip from which I removed redundant elements (unnecessary resolutions), removed files i don't use, dll's ... no skin, no extra ux's, minimalistic sys with added only speedcam section described on Forum.
As for 3D, you should use the "lightest" DEM file. I have described everything else that needs to be applied in [Only registered and activated users can see links. ]

However, the general problem with MIO devices is that the UI is adapted to their software. Such a weak device wastes resources on running services that are not being used.
It is better to buy a generic (Chinese) device without any software and insert iGO. Even some 5" branded can be found second hand for a little money.