well for 1 your video driver is OLD over a year old according to your DX diag
you should update those to the latest Catalyst Omega Drivers
found here
http://support.amd.com/en-us/download
what model is your 7900 series AMD card is it a 7990 dual GPU video card ?
if so that may cause an issue as well since crossfire is still broken for far Cry 4 and AMD even disabled Crossfire support for the game on the driver level
so you cant even over ride it to force crossfire to work until both Ubisoft as well as AMD fix the issues along with an updated driver package
- The AMD CrossFire™ profile for Far Cry 4 is currently disabled in this driver while AMD works with Ubisoft to investigate an issue where AMD CrossFire™ configurations are not performing as intended. An update is expected on this issue in the near future through an updated game patch or an AMD driver posting.
for now tho id suggest you try the latest Driver from AMD for your video card as well as verify your game files and see if that resolves your crash issues