If I have a steel dust pattern from Refined Storage on my inventory my fps drop from 100 to under 10 and make the game unplayable, it still happens if u drop the pattern on the ground and look at it.

(pattern)

(without the pattern)

(with the pattern on inventory)

(with the pattern on the ground)

I also encountered this a while back, should have reported, I think it's something to do with the hammer, as any dust recipe using hammer also drops in a similar manner. Solution for me was to autocraft using a mixer with the hammer already in it.