NVIDIA interview questions

After applying on the Website i got email from their recruitment dept proposing a phone interviews. I actually had 2 phone interviews, the audience was more o less the same : hiring manager, his Boss, dept Director : one hour spent presenting myself and doing kind of simulation about possible situations they proposed. I got no feedback but after few months an invitation for a new phone call ( same audience) more or less same topics...... the content was more or less the same , this time apparently results was good and in 2 weeks i got the invitations for a F2F interview. I was asked always introduce myself and guide them through a simulated case respond few technical questions, why i would prefer join them rather then stay in my current company . Hiring manager was rude, i had the feeling was playing a role just to check how i react under stress , or perhaps he had simply a bad day.... nevertheless unpleasant , the other 2 Eng attending the interview were decent (at least them). in 2 weeks a got a call for a new F2F interview , this time was very long (4 hours ) and i met team, director, HR and other people that the hired resource have to work with. Out of this process I never got any feedback: simple as is they have not even provided an automatic email to give a feedback . Personal consideration: I was not that convinced by the company (expecting much better really), i have a certain experience and I have been working for more than one Automotive semiconductor company: Nvidia hiring process, as far i saw , doesn't exist at all , is chaotic , delayed, redundant , they look for professional and at the same time they show to be unprofessional. Very bad experience