Caporegime
When you say stock, do you mean your card's default clocks or 290 defaults clocks of 947/1250?
1040 / 1350, its factory overclocked
I think the problem is the individual core performance of your CPU, Heaven 4 is not realty effected by this and is just about having enough speed.
If you have got Tomb Raider it may be an idea to give that a run to compare or you could give Valley a run as well.
The CPU shouldn't effect the GPU score in Firestrike, and it is running flatout...
Same with Sniper Elite V2, The GPU is flatout all the way through, i put the MSI Screenie up in your thread, you can see the GPU usage.
I will do Tomb Raider next
PS: Dirt Showdown seems ok if a little bit low, 91 FPS, i was expecting about 93/94, but that's not bad.