Assuming there is alot 1x slot of room between the two of them
Try one of these -
http://www.frozencpu.com/products/15508/vid-182/Titan_Adjustable_Dual_Fan_PCI_Slot_VGA_Cooler_TTC-SC07TZ.html?gclid=CKLGyLz5o7kCFcaDQgod9UYAbw
Bitcoining is not a typical load for a GPU it is basically...
I think before anyone can attempt to help you?
You got to post more details ie - what games?
How many displays and resolutions are you attempting to run the games at?
1080P Max out settings ie - ultra everything is going to push a video card to the max vs. just running at old school 800...