There is a version of Furmark available for Linux in the form of GPUTest. For maximum torture, I suggest running both MPrime and Furmark, at the same time. This uncovered an issue I recently experienced.
I recently upgraded the GPU in my “Steam machine” to an Nvidia 980Ti. It dual-boots between Linux and Windows, because you know, games… I noticed that some games would now crash in Windows, but not in LInux (with my old 660ti GPU, they were both stable). First I thought “that’s just Windows”, but it didn’t seem consistent with the kind of flakiness I have come to expect in MS-land. There were no bluescreens, the computer just rebooted. And the fact that it was really stable with the old GPU made me suspicious.
MPrime was stable, but running Furmark almost instantly triggered a reboot. Digging into the system logs, everything pointed to the Power Supply, a measly 600W, being just too weak to power the system under full load. But Furmark was stable in Linux, which was weird. Turns out, I had to run both MPrime and Furmark simultaneously to reach the same power consumption under Linux. And sure enough, the system instantly rebooted.
Upgrading to a 1200W PSU solved that. (It’s not overkill, it’s a safety margin!)