Where t is the time for a problem size of 1
speed = (t(n^m))/hardware_speedup
A bit of algebra and we get...
((speed*hardware_speedup)/t)^(1/m) = n
That is, for, say, an order n^2 algorithm your speedup from hardware on a similar sized problem gets thrown under a big-ol square root. Such that, if your code sucks, "...aiming to use the power of the modern consoles to push the game engine as far as it would go" won't get you nearly as far as you would hope.