01-04-2018, 04:47 PM
Did you set the fan speed up? 33% is very optimistic for a 7990. They should run >70% all the time to keep the temps down. Plus the upper card (device 1) has some temp issues, you can detect that at the higher GPU temps while the fans also spins much higher. Maybe you can put both cards further apart or ramp up the airflow in your case. Or you can put an old card in between to shield one GPU from another. As long as the downer one has enough room to breathe of course 
Or the CPU is at some kind of limit with I/O- and/or Interrupt-handling.
Or the CPU is at some kind of limit with I/O- and/or Interrupt-handling.