B4 isn't going to stress your machine like a stress test will. If you are passing the stress tests and memtest you can pretty much rule out the cpu and RAM causing the crashes. try these settings in Nvidia control panel, then manage 3d settings.
Ambient occlusion - Off
Anisotropic Filtering - App controlled
Antialiasing FXAA - Off
Antialiasing - Gamma correction - On
Antialiasing Mode - App Controlled
Antialiasing - Transparency - Off
Cuda - GPU's - All
Maximum Pre-Rendered Frames - 2
Multi- Display/Mixed GPU Acceleration - Single Display Performance Mode
Power Management Mode - Prefer Maximum Performance
Texture Filtering - Quality - High Quality
Threaded Optimization - On
Triple Buffering - On
Vertical Sync - App Controlled
For the SLI setting keep that to Nvidia Recommended
Enable V-Sync in Battlefield 4 when you start it.
Now, click the program settings tab, is battlefield 4 listed in there? If not click the add button and add Battlefield 4. Make sure the settings are as listed above. This is how I have my machine set up and all my games play great. I will say this when I have SLI enabled and I play Far Cry 3 multiplayer, after every match and I mean EVERY match the game freezes. It is a known issue.