I'm trying the AT2 dev 2 since 3 hours now and it's much much better.
High cpu is gone and we can use unity editor with AT2 manager activated.
Texture build time is much much speeder

DX11 is ok and the new hardware level is very cool.
One problem. It crashed when i added a directory with more than 1000 materials and 700mo of textures.
My brother is still modifying the nda but the hdd is ready to go with all the data.
David