Why don't we have 12V CPUs?

[AtorCZ]

Hi,

for the past couple days I've been wondering why don't we use higher voltage CPUs.

ofc I've been looking through google but all I found (unsurprisingly) was talking about 12V rails, extension cables, 12V CPU fans, pumps etc. (in a nutshell I got bored from just scrolling endlessly)

Most of my thinking was triggered by the video discussing the new 12V PSU standard and from that point I've been playing with thought of 12V CPUs. I know that in past (like pentiums from 1990-1995) used 5V with (most probably) lower current than they use today. But I don't know why and I really do wonder. I don't have any electrician as a friend who could explain me. Google (and other forum threads) I gave up on when I saw over 1000 irrelevant topics.

 

I just was unable to find the answer to WHY not.

 

My thoughts: Why 12V CPU?

First of all it could be more power efficient with power delivery (I don't remember the equation but i know the higher voltage gets the less power losses there are)

PSUs and MOBOs could be freed of all the VRMs necessary for conversion to lower voltages

Maybe even less heat from the components as there would be less current coming through?

Thanks to less current and heat you'd get longer life span out of the CPU?

 

Why not?

Does the CPU and other components need some specific amount of current to even run?

I cannot come up with any others.

 

All of my knowledge comes from elementary and high school education so I may very well be wrong or I'm missing an important piece of a puzzle to fill the gap of "why not?"

I'd appreciate clarification to this topic.

[Origami Cactus]

Silicon (the material cpus are made out of) absolutely doesn't like high voltage. It degrades really quickly.

So until we made cpus out of sand, no high voltage cpus for you. AFAIK graphite cpus can take more voltage, but they don't exist yet.

[Haro]

Afaik it would kill the cpu immediately, cpu's don't need that much voltage and the voltage regulation on the board is needed and the silicon can't handle that voltage.

10 hours ago, AtorCZ said:

be more power efficient with power delivery (I don't remember the equation but i know the higher voltage gets the less power losses there are)

PSUs and MOBOs

How? 

[iLostMyXbox21]

2 minutes ago, Origami Cactus said:

Silicon (the material cpus are made out of) absolutely doesn't like high voltage. It degrades really quickly.

So until we made cpus out of sand, no high voltage cpus for you. AFAIK graphite cpus can take more voltage, but they don't exist yet.

“So until we made cpus out of sand”

 

**laughs in florida**

[igormp]

10 minutes ago, AtorCZ said:

Hi,

for the past couple days I've been wondering why don't we use higher voltage CPUs.

ofc I've been looking through google but all I found (unsurprisingly) was talking about 12V rails, extension cables, 12V CPU fans, pumps etc. (in a nutshell I got bored from just scrolling endlessly)

Most of my thinking was triggered by the video discussing the new 12V PSU standard and from that point I've been playing with thought of 12V CPUs. I know that in past (like pentiums from 1990-1995) used 5V with (most probably) lower current than they use today. But I don't know why and I really do wonder. I don't have any electrician as a friend who could explain me. Google (and other forum threads) I gave up on when I saw over 1000 irrelevant topics.

 

I just was unable to find the answer to WHY not.

The CPU itself has a somewhat fixed maximum "resistance", which means that for a given voltage it can only use so much current. Want to give it more juice? Increase the voltage so it'll be able to draw more current.

 

If you increase the voltage by ~10x (CPUs nowadays work around the 0.9~1.2v range), you'd be giving it 10x more current, which would make for a nice fireball and burn everything away. Increase the resistance in order to limit the current and now you have tons of wasted energy in form of heat due to it.

 

Quote

First of all it could be more power efficient with power delivery (I don't remember the equation but i know the higher voltage gets the less power losses there are)

Power delivery is already done at 12v, so losses between the 12v -> VRMs -> CPU isn't that bad.

An example on that is that new 12VO PSU, where they got rid of the other lower voltages and only deliver 12v to the motherboard, which then takes care of voltage regulation.

[Moonzy]

3 minutes ago, TofuHaroto said:

How? 

P = I^2 R, given a material with the same resistance, the lower the current, the less power

P = VI, higher voltage = lower current needed for the same amount of power to load.

this is why electric towers operate on kV scale, and use transformers to step down voltage before delivery.

but im not too sure how applicable it is in chip design.

 

but to answer OP, because silicon based transistor's gate voltage is around 0.7v

it's a material limit, not a limit by design if i had to guess, not too into chip design

 

12 minutes ago, AtorCZ said:

PSUs and MOBOs could be freed of all the VRMs necessary for conversion to lower voltages

unless your wall voltage is 12v DC, you'll still need some sort of conversion

not to mention wall power are often dirty, and requires regulators to stabilise for computer chips usage

 

14 minutes ago, AtorCZ said:

Maybe even less heat from the components as there would be less current coming through?

mmm depends on the material used for higher gate voltages.

 

basically tl;dr, to use 12v input to the CPU to operate directly would require a new material to be used as the transistor.

[Haro]

10 hours ago, Moonzy said:

given a material with the same resistance, the lower the current, the less power

Yea im aware of the that lol, i just don't think i understood OP correctly but if i did, i don't see a point in that, but i could've misunderstood  that..