Effect of Feature Size on Performance
f is the size of basic lines on chip and is now 0.25nm and will decrease inexorably to 100 nm in 2005-2010 time period
- 1992 Digital alpha chip was f= 750 nm. feature size and 1.7 x 106 transistors
- 1995 Sun UltraSparc was f= 500 nm. and 5.2 X 106 transistors
Roughly number of Transistors is proportional to (1/f)2
Speed of chip is proportional to (1/f)
- This is no longer true as “wires” get so thin that propagation speed decreases and so clock speed levels off around 1 gigaherz
Figure of Merit is (1/f)3
Die size is also increasing like (1/f) and this enhances effect!