Check your preferences and see if graphics processor is enabled. Then click on advanced settings Make sure used graphics processor is enabled. Use open cl is not required, but if you can use it, enable it.
If any of these settings are grayed out, then one of the following needs fixing.
Ram - 512 MB of video ram
video card driver
Video card itself
You can update the video card driver other than that you may need to replace the video card.
Here is the list of specs for photoshop. Make sure your system meets or exceeds the specs for flame filter to be available to you.
Just an oddball thing I want to add.
My Dell is 3D capable, My Macbook is not. Frame, Flame, and Tree are all dimmed out.
I activate Frame.Tree, and Frame on my Dell using a 3D > New Mesh from Layer > Postcard.
Then I sync my Preferences with my Mac.
Very surprised to find all three Filters now activated on my Mac and performing normally. Works for CC and CC 2014.
A great workaround if you do not have 3D capabilities but your other computer does.