4 ms·

I had a similar realization when it dawned on me that my computer performed about twenty instructions before the light from my monitor arrived at my cornea...

by yan 17y ago

I had a similar realization when it dawned on me that my computer performed about twenty instructions before the light from my monitor arrived at my cornea... (edit: light travels about a foot in a nanosecond, or 6 inches per clock cycle in a standard 2ghz pc. multiple simple additions can be done in a single clock cycle; multiple by number of cores)

maukdaddy 17y ago
Wow that's an amazing way of looking at the computing power and speed of modern processors. Maybe Intel should start marketing processor functionality this way!
ars 17y ago
Tthe speed of light is starting to impact how fast cores can be. They need to take it into account when routing signals on the core. And it's one reason asynchronous cores work a lot better, since at high hz it's impossible to keep the entire core synchronized.
- yan 17y ago
  As I understand it, it has been an issue and a major reason for actual cores being as small as they are. The time a signal takes to propagate from one section of the core to another is significant.
  - anamax 17y ago
    Chip sizes are a function of yield and performance. Core sizes are designed to optimize performance for a given chip size. (Yes, there's a circular dependence but yield is a huge factor in chip size.) That said, it's been at least a process generation since a given clock signal could be used to synch events on the opposite sides of a core, let alone a (high performance) chip. This is due to both increasing clock frequency and the fact that propagation speed has gone down as feature size decreased.
- baddox 17y ago
  Electric current in copper does not travel anywhere near the speed of light. In fact, motherboards using fiber optic buses instead of copper buses may be one solution to the problem you're talking about.
joeyo 17y ago
And when you consider how much longer it takes for you perceive, the light it gets even more ridiculous!

by yan 17y ago

maukdaddy 17y ago

Wow that's an amazing way of looking at the computing power and speed of modern processors. Maybe Intel should start marketing processor functionality this way!

ars 17y ago

Tthe speed of light is starting to impact how fast cores can be. They need to take it into account when routing signals on the core. And it's one reason asynchronous cores work a lot better, since at high hz it's impossible to keep the entire core synchronized.

yan 17y ago
As I understand it, it has been an issue and a major reason for actual cores being as small as they are. The time a signal takes to propagate from one section of the core to another is significant.
- anamax 17y ago
  Chip sizes are a function of yield and performance. Core sizes are designed to optimize performance for a given chip size. (Yes, there's a circular dependence but yield is a huge factor in chip size.) That said, it's been at least a process generation since a given clock signal could be used to synch events on the opposite sides of a core, let alone a (high performance) chip. This is due to both increasing clock frequency and the fact that propagation speed has gone down as feature size decreased.
baddox 17y ago
Electric current in copper does not travel anywhere near the speed of light. In fact, motherboards using fiber optic buses instead of copper buses may be one solution to the problem you're talking about.

joeyo 17y ago

And when you consider how much longer it takes for you perceive, the light it gets even more ridiculous!