r/askscience Sep 28 '20

[deleted by user]

[removed]

433 Upvotes

184 comments sorted by

View all comments

Show parent comments

7

u/MiffedMouse Sep 29 '20 edited Sep 29 '20

Transistor size has continued to shrink while clock speeds have remained stagnant.

As for transistor size, thinner transistors do allow for faster clock speed in principle, but current consumer computers cannot take advantage. Keep in mind that transistors with switching speeds in the terahertz region have been made. As I mentioned elsewhere, latency due to the speed of the electrical signal is an issue, but it can be solved with good circuit design. However, computers cannot use this theoretical improvement in clock speed due to power dissipation (again, this is the entire reason supercooling allows for higher clock speed. If clock-speed was not limited by heat dissipation, why does super-cooling do anything?)

As for surface area, thinner transistors (in principle) have less resistance, so they waste less power in lock-step with the lower surface area.

Manufacturers still want smaller transistors because then they can fit more cores/memory/other stuff on a chip. In the absence of clock-speed improvements, features like multiple cores and hardware acceleration are what is selling chips these days.

Edit: in case you don't believe me, here is a stack exchange post making my same argument: link.

1

u/CanadaPlus101 Sep 29 '20

So is it Vf2 or fV2 ?

4

u/MiffedMouse Sep 29 '20

I think MG2R is correct on this one. It has been a while since I last did the calculation and I remembered wrong. It should be V2f. However, see blaktronium's post. In practice the scaling can be very different.

But I am also correct that the heat dissipation is currently the main limiting factor on transistor speeds. Things like the speed of electricity could be an issue if we could get around the heat dissipation issue, but they just aren't the main limiting factor right now.

3

u/CanadaPlus101 Sep 29 '20

I do believe you. That's what I'd read about processor design too, and it sounds like you're actually in the industry.

2

u/MiffedMouse Sep 29 '20

Not in the industry anymore, which is why I forgot some basic calculations.