Wow... it was really interesting to see even though the data recorded was just a few minutes.
So, first of all, before and after running Furmark, there seems to be something using your HDD at 100% both reading and writing, from the logs I can tell you it's not the pagefile nor some hefty download/upload in your network-internet, so that's something you need to find out using procexp.
Now into the Furmark test, your GPU reaches 92ºC+ and before the crash it gets up to 3872253 memory errors, that's obviously causing the crash, the errors start to accumulate when your GPU reaches 89ºC which coincides with a current spike of 258W into the GPU.
To this I must add that your PSU's 12V+ line drops to 11.737v and in the GPU to 11.313v, both values are not good, it shouldn't drop below 11.8xxv.
You need to solve the temp situation first, the instability that it causes could be the reason the 12V+ line is dropping below expected values, seeing some reviews your GPU should never go above 80ºC. If after fixing the temp the 12v+ still drops that much then you'll need to consider getting a better PSU, your CPU is also getting affected causing two of your six cores dropping from time to time from their 4.2ghz (4118mhz in log) to 1.7ghz to get immediately back to 4,2ghz, your CPU temps are fine so this is the result of power instability.
Make sure your GPU fans are working and if necessary you'll need to replace its thermal paste.