Hello Alexei,
thanks for your answer.
I have the last drivers (320.49) but I still have this problem.
Sometimes Photoscan uses GPU, sometimes not, and the difference in time calculating is amazing.
If I call the task manager, Photoscan crashes.
I think you're true, it's a problem of driver. Nvidia already had this type of problem with Photoshop.
I also read on forums this bug sometimes come when you have at least 32Gb of RAM.
Do you know if anyone else has this problem with Nvidia GeForce + 32Gb ?
Thanks.