How fast can a serial computer be?
Consider the 1 Tflop sequential machine
- data must travel some distance, r, to get from memory to CPU
- to get 1 data element per cycle, this means 10^12 times per second at the speed of light, c = 3e8 m/s
- ==> r < c/10^12 = .3 mm
Now put 1 TB of storage in a .3 mm^2 area
- each word occupies about 3 Angstroms^2, the size of a small atom
1 Tflop 1 TB sequential machine
James Demmel is the author of this slide