As you're getting a BSOD, it almost certainly isn't a GPU overheating problem. Overheating causes hangs or in the case of some graphics cards, artefacts but not BSODs as a BSOD happens within program code, not something the GPU runs.
Looks like lm-sensors is working, otherwise there'd be no temperatures in ksysguard.
As I said, there's still no temperature monitoring software under Linux that's as good as Speedfan, so repeat with Speedfan and set it logging while you run Furmark and Prime95. There can be very quick changes in temperature given different power states that modern CPUs and GPUs run at so hence you need to monitor it, not just see what it is after activity finishes.
I'm at least a reasonably tolerable person to be around - Narcopic