This was the chat with the nvidia support , here have a look :
Zia: Hi, my name is Zia. How may I help you?
Pranav Rawat: Hi! I own a Lenovo y50-70 laptop with nvidia GTX 860m graphics card. Lately after installing 378.49 Driver, my windows is crashing and freezing. Most of the time i get a BSOD saying clock_watchdog_timeout.
Zia: I apologize for the inconvenience caused and I'll do my best to assist with the issue
Zia: Have you over clock the card?
Pranav Rawat: No my card is not overclocked. I have tried clean installation. I also have resetted and updated my windows 10.
Zia: Please install the below driver and see if it helps:
http://www.nvidia.com/download/driverResults.aspx/113444/en-us
378.49 is game ready driver for Resident evil 7, if you have the same game installed then only it would help with this driver or else you may revert back to previous driver as above and check
Zia: NOTE: Please select Custom (Advanced) while installing the graphics drivers and on the next screen please place a check mark on perform a clean install
Pranav Rawat: Yes the previous versions work totally fine.
Zia: Then please use the same till we release next driver
Pranav Rawat:
http://www.tomshardware.com/answers/id-3312531/nvidia-geforce-driver-378-causing-crash.html
^but about the 378.49 , i am certainly not the only one with this problem.
Zia: Yes, we are aware about this
Pranav Rawat: Alright, so do i hope that the next release of the driver would be perfectly fine?
Zia: Yeah, it should be, however could you help me with the dmp file for bsod with that driver so we can escalate the case as well
Pranav Rawat: Umm actually i just had to reset my windows 10 because the bsod wasnt letting me sign in. So i don't think i'll be able to provide you with that.
Zia: Oh, we need dmp file so we can forward the case to l2 team and they need to analyze the dmp file for root cause of the issue
Zia: Or if you want you may wait till next driver release
Pranav Rawat: Umm what i can do is, i can ask people on the forum experiencing the same issue and get you the dmp file.
Zia: You may update the same driver 378.49 then if you came across Bsod it would generate DMP file in window
Pranav Rawat: Hahaha, i really had a very hard time because the BSODs as i almost got locked out and would have lost my data, So i am refraining to install the driver again, but as soon i'll get the dmp file from someone else via this forum:
http://www.tomshardware.com/answers/id-3312531/nvidia-geforce-driver-378-causing-crash.html
I'll get back to you.
Zia: Sure, thank you for all your efforts and I am sorry for the trouble due to this
Pranav Rawat: Ah, its okay it had happened earlier with some of the drivers around last year and all the 860m users got a stable and a working driver after the next 3 releases. I hope Nvidia figures the problem this time a bit earlier.
Zia: Sure, we will do that
Pranav Rawat: Thanks. Should i disconnect?
Zia: Sure, you may
Pranav Rawat: Thanks again, bye
You have disconnected.