During play, the game frequently crashes. Suspect the issue is due to the Nvidia GTX 560 card as before upgrading to this card the crashes didn't occur.
The game crashes about once per 1-2 hours in stable version 0.43.116251 but much more frequently - every 30 minutes or so - in experimental version 0.44.123800. Crashes can occur in any environment/situation.
When the game crashes to black screen it can usually be resolved by going to task manager and ending the DayZ.exe process then restarting the game but occasionally the computer has to be hard reset.
I have tried nvidia driver versions 337.50 (beta), 335.23, 334.89 & 334.67 with no difference observed.