I have tall ram. I have one thats Vengence and another brand that is about the same height. I also have a Gigabyte GA-990FXA-UD3 ATX AM3+
motherboard. Will this cpu cooler fit?
No, it will not clear the Vengeance RAM. I had a similar situation and I solved the issue by grinding off 1 mm x 10 mm along the bottom side of the fan.
I know that others have raised the fan sufficiently to clear the RAM. My RAM is Corsair Vengeance.