My specs are:
Intel Core i5 4460 not overclocked 3.2 GHz
MSI GTX 970 4 GB
8 GB DDR3
600 Wats Power Source.
The game runs absolutely smoothly on the highest detail level, but it crashes since the 1.04 patch.
I have the NVDIA WItcher 3 ready drivers which were released on the day the game came out.
Hmmm everything seems ample enough to run without a problem. Do you know if your PSU supplies at least 50 amps on the 12v rail? You have enough wattage, but the 970 is known to have power spikes which may be causing the card to "malfunction", plus the 970 requires at least 30 (I believe) amps on the 12v rail, but 50 is just to make extra room for those power spikes.
Look up the specs of your PSU and make sure you can supply 50 amps on the 12v rail you are using.
When I got my GTX 970 I had to make each 6 pin connector run off of a different rail even though I have a 1600W psu. I was pulling too much running both 6 pin connectors on one rail alone and i kept getting errors when playing Arma II. I would play for hours fine, then all of a sudden when I got in a heli, the game would crash with a GPU related error. As soon as I ran each connector off of a different rail, I havent had a problem since with any game.
Like I stated, check your PSU's specs and make sure you have 50 amps on your 12v rail, if need be run one 6 pin connector off of one rail, and use a separate rail for the other 6 pin connector