It is too slow. Signals must move to and from memory at velocities less than the speed of light. No matter how fast information can be processed, only God can reduce the time it takes to fetch instructions and data from memory. Thus far, there is no sign of divine intervention. That's the gap between processing speeds and memory access times.
Processing speeds depend largely on a chip's clock rate.
New chips will be broken into separate modules, sized by the need to make all parts of the chip accessible during an on-off cycle, a constraint fixed by the systole of a light pulse, Mr. Gilder says. He maintains that this limitation will be overcome by developing optical computing technology and using more bandwidth to economize on increasingly costly and constrained processing devices. Thus, the telecosm is dominated by lightwaves inside chips, computers, and networks. Network design historically has been driven by the relative costs of switching and transmission. Modest swings in preferences for distributed or centralized processing have resulted from the uneven pace of progress in those two domains.