Hai buddy, not sure if this may be your issue but make sure to disable the 2D Clocks Before you apply your overclock, alternatively you can try setting your 2D clocks and voltage higher, either way seemed to work for me.
I had the same problem when overclocking my 6950, it would run 3D games fine when overclocked but would crash when going from 3D to 2D, I discovered through trial and error that this was due to the sudden frequency/voltage changes.
Hope that helps
🙂
Chassis: NZXT Switch 810. - MB: Rampage v Extreme x99. - CPU: Intel Core i7 5820k. - Memory: 16GB Ripsaw 4 DDR4 2400MHz. - GPU: 2x Sapphire Tri-X R9 290 OC Edition 4GB.
PSU: Corsair AX1200i. - Storage: 1x Samsung 830 60GB SSD + 1x Samsung evo 840 120GB SSD + 1x Samsung 850 Evo 250GB SSD + 1x Seagate Barracuda 500GB HDD.
OS: Windows 10 Pro x64.