In photoshop CS6 when using a brush to paint, the actual painted brush mark is smaller than the preview of the brush size.
Incase i mixed you up with my explanation, I’m attaching a pic that shows (on the left) the size of the selected brush and how small is the painted mark. And on the (left) what i see on a different computer where the brush's size is the same of what is actually painted.
note: the colour i paint is white and the black circle is the brush size preview.
Its very strange because i know that what is painted should be exactly the same diameter of the brush. But that is not the case on the left sample.