Msi Afterburner is just the gpu, so your card will have good airflow. That's got nothing to do with the cpu cooler. Everybody will agree that the cooler the air you supply to a heatsink, the more affective it is, so imagine your gpu is putting out some very warm air when gaming. That air is rising up past your cpu heatsink. The D92 is sacking in warm air, not cooler air like when you aren't pushing the gpu. So your D92 is running the fans slow, because the fan curve is low. But, that heated air is making the cooler less affective at cooling the cpu, so temps go up. When you push the gpu hard, you'll need a more aggressive fan curve on the cpu, making the fans spin faster at lower temps, which even though it's warm air, it only has to absorb a little heat before going out the exhaust, being constantly replaced by fresh air. With slower spinning fans, it takes longer to replace that one small section of air, so that air is forced to absorb more heat than it wants to, at a slower rate of absorption, so cpu temps go up.
Instead of 30% fan at 30° ~ 50% fan at 60° and max at 70°, run your CPU fan at 30%-30°~75%-50° and max at 60°. Your temps will drop. Furthermore, set system fans to 50% at 30°~max at 40° which will provide more cooler air into and out of the case, since case temps are really different to cpu or gpu temps. Honestly, case temps shouldn't be much higher than your ambient temp, just a few degrees at most.