Hacker News Reader

At 10GHz, a signal can propagate no more than 300 microns in a cycle due to the speed of light. The CPU would have to be designed either asynchronously or with many more clock domains than currently. The performance probably wouldn't scale linearly by any realistic metric, and you'd still have the same memory latency.

View on HN

Your math is two digits off. Using Grace Hopper's "one nanosecond is one foot", one cycle at 10 GHz is 1/10 of a foot or 3 cm. That's 30,000 microns not 300.

But yes, the speed of light limitation on signal propagation is a major factor in our current limit of 3 to 4 GHz chips.

Arguably the previous poster only mentioned he wants a 10GHz processor, not fast off-chip memory accesses. Also you can achieve a lot of performance in signal processing applications using a fast-clocked single core with on-chip SRAM scratchpads.

Reply on news.ycombinator.com