Quick note on "perceivable" vs benchmark speeds as above ^, it takes about a 25-30% difference in speed for most people to notice that one thing is faster than another when it comes to how fast a system does something just by looking at it. So going from say 30fps to 35 fps is not likely to be noticed, but 30-40 or 30-50 would be. Anything under that point you get to "well, it may be faster, maybe not, or just a little, it's hard to tell".