Apart from the detail map [obviously], you can use these files from Post #1:

3D building/landmarks map - gmap3d.img

Junction View file - High resolution split screen JCV D3048140A.JCV

G2S file - D2925140A.G2S

Your 3790 also uses ASR'1' files which are available in Post #43 or #44. This note is also in Post #1: Nuvi 23xx_37xx ASR1 files in post #43/44.

If your unit is not performing properly, update firmware if necessary and hard reset it anyway. Back up your data before resetting it.