Yes the original was 105mm and people would pair that with the Arctic Accelero Xtreme which would sit directly on 2x120mm bottom mounted fans.Interesting, I will have to look at my M1 and see how it would work. I do have the slim Noctua fan on the side blowing down onto it, so there is that. I assume the original C14 was shorter to allow for the 25mm fan to fit above it?