GPGPU (general-purpose graphical processing unit) techniques can result in a lot more than a fivefold increase for some applications. It's a new technology that I studied a bit and am incredibly impressed with the implications of - the basic idea involves using the GPU to do analysis of a texture or mesh using per-pixel or per-vertex operations, and then passing that information back to the CPU.
For instance, let's say you have a texture you want to divide into individual areas and do something like a luminance analysis on (the classic looking-for-dark-areas in an x-ray). You can take a high-resolution texture, run it through a very specialized pixel shader, and then blit it to a smaller texture, then read that texture data back. As an example, let's say you have something like a 1500x1500 texture that you'd like to analyze in terms of smaller regions - blit the whole thing through a specialized scientific pixel shader onto, say, a 10x10 texture, and suddenly you've divided a 2.25million pixel image into 100 unique sections that are already partially analyzed. Read back a single pixel from the new texture and it will provide detailed information about one-one-hundredth of the original, without having to actually iterate through 22500 pixels in the CPU, which is very slow. A CPU is relatively slow at doing image processing or any kind of work that involves a texture or 3D mesh. GPUs are not, and therein lies the potential of these techniques.
My guess is that a staggering number of research developments will result from greater mastery of GPGPU theory and tech, which is very much in its infancy.