A Google search will also show that Nvidia mobo's are known to have an issue with the Northbridge running hot. Are you using the water-cooling feature of the NB? I would apply new paste just to make sure it's not an issue.
One of your video cards is running significantly hotter than the other when both cards are installed. It's usually the bottom card that runs hotter because it's blocked in and doesn't get the ventilation of the other card. The paste could be degrading/drying and out and causing problems that aren't noticeable with just one card.
Your Voltages don't look bad but there also not under any strain at all. Try running a Benchmark like LinX or SuperPi and watch your voltage during the test and see if any of them fluctuate. Open HW Monitor and HWMonitor will both keep track of the high and low values so while the system may not crash, we still may see a problem.
One of your video cards is running significantly hotter than the other when both cards are installed. It's usually the bottom card that runs hotter because it's blocked in and doesn't get the ventilation of the other card. The paste could be degrading/drying and out and causing problems that aren't noticeable with just one card.
Your Voltages don't look bad but there also not under any strain at all. Try running a Benchmark like LinX or SuperPi and watch your voltage during the test and see if any of them fluctuate. Open HW Monitor and HWMonitor will both keep track of the high and low values so while the system may not crash, we still may see a problem.