4 ms·

What does nm measure these days? I hear it's just a marketing term at this point, but "1.8" seems like a specific enough number that it must be measuring someth

What does nm measure these days? I hear it's just a marketing term at this point, but "1.8" seems like a specific enough number that it must be measuring something.

ddulaney 4y ago
Nothing anymore. Originally it measured a specific dimension on the transistor. Then transistors started shrinking non-uniformly, so they adjusted it -- "how big the transistors would be at equivalent density if they had shrunk evenly". That's an easy thing to play with though, and so you see more and more departures from reality.
KptMarchewa 4y ago
It's like RHA on tank armor.
- zamnos 4y ago
  took me a second to find the meaning of RHA https://en.m.wikipedia.org/wiki/Rolled_homogeneous_armour https://en.m.wikipedia.org/wiki/Rolled_homogeneous_armour
- aidenn0 4y ago
  I can't decide if that's an excellent analogy or a terrible one. On the one hand it's very true, on the other hand I suspect the fraction of HN readers who are familiar with tank armor is fairly small. For those not familiar, RHA is the type of armor used circa world-war II. Armor has gotten better on a per-inch-thickness with improved technology. Modern tanks (and modern anti-tank munitions) are often rated as to the equivalent thickness of RHA protection (or penetration) they provide. For example, Explosive Reactive Armor (ERA) can have a very high RHA rating if you use a traditional HEAT (High-Explosive Anti-Tank) round as your benchmark, but a tandem HEAT round can almost completely eliminate the per-thickness protection advantage that ERA offers. So a tandem HEAT round might have a lower RHA penetration rating than a traditional HEAT round, yet be more effective against an ERA with a very high RHA rating. So, if you have a spiffy new tandem HEAT round, and want to fake^H^H^H^H present good numbers, you find the highest RHA rated ERA armor that it can penetrate and claim that as the RHA rating of your projectile. Even though it might not be able to penetrate that many inches of actual RHA, or possibly even modern composite armor with such an RHA rating.
  - regpertom 4y ago
    Which is to say something called RHA was the metric used for tank armour measuring, but it got gamed more and more and is now unreliable on the face of it except for rough jists? Do you think that marketing will drop to pico or zero point whatever nano?
babypuncher 4y ago
Minimum feature size. The problem is that we've reached a point where not all features scale down evenly. So while some transistors might be 2 nm on a new process, others are largely unchanged from 3 or 5 nm. How much you get out of a new process is now highly dependent on how you design your chip and what you want it to do. This is why AMD is using multiple processes in a single CPU package these days. Some elements of their processors get little or no benefit from smaller nodes, so it's cheaper to make them on an older node.
- adastra22 4y ago
  I believe it doesn’t even measure that now. It’s pure marketing numbers, albeit industry wide instead of the fault of any one company.
Dalewyn 4y ago
>What does nm measure these days? Not Much.
imtringued 4y ago
It refers to the theoretical dimensions that a planar transistor would have to achieve the same density. Nobody uses planar transistors these days. Instead, 3d multi channel transistors are being used. The number is supposedly referring to the gate length of the theoretical planar transistor. If your transistors can reuse the same gate to drive three different channels, that means the effective gate length would be one third but once you open this can of worms, the numbers can be chosen arbitrarily to mean whatever you want.
- Kye 4y ago
  It's like knots. No one's dropping a knotted rope into the water to measure speed, but the term persists.

What does nm measure these days? I hear it's just a marketing term at this point, but "1.8" seems like a specific enough number that it must be measuring something.

ddulaney 4y ago

Nothing anymore. Originally it measured a specific dimension on the transistor. Then transistors started shrinking non-uniformly, so they adjusted it -- "how big the transistors would be at equivalent density if they had shrunk evenly". That's an easy thing to play with though, and so you see more and more departures from reality.

KptMarchewa 4y ago

It's like RHA on tank armor.

zamnos 4y ago
took me a second to find the meaning of RHA https://en.m.wikipedia.org/wiki/Rolled_homogeneous_armour https://en.m.wikipedia.org/wiki/Rolled_homogeneous_armour
aidenn0 4y ago
I can't decide if that's an excellent analogy or a terrible one. On the one hand it's very true, on the other hand I suspect the fraction of HN readers who are familiar with tank armor is fairly small. For those not familiar, RHA is the type of armor used circa world-war II. Armor has gotten better on a per-inch-thickness with improved technology. Modern tanks (and modern anti-tank munitions) are often rated as to the equivalent thickness of RHA protection (or penetration) they provide. For example, Explosive Reactive Armor (ERA) can have a very high RHA rating if you use a traditional HEAT (High-Explosive Anti-Tank) round as your benchmark, but a tandem HEAT round can almost completely eliminate the per-thickness protection advantage that ERA offers. So a tandem HEAT round might have a lower RHA penetration rating than a traditional HEAT round, yet be more effective against an ERA with a very high RHA rating. So, if you have a spiffy new tandem HEAT round, and want to fake^H^H^H^H present good numbers, you find the highest RHA rated ERA armor that it can penetrate and claim that as the RHA rating of your projectile. Even though it might not be able to penetrate that many inches of actual RHA, or possibly even modern composite armor with such an RHA rating.
- regpertom 4y ago
  Which is to say something called RHA was the metric used for tank armour measuring, but it got gamed more and more and is now unreliable on the face of it except for rough jists? Do you think that marketing will drop to pico or zero point whatever nano?

babypuncher 4y ago

Minimum feature size. The problem is that we've reached a point where not all features scale down evenly. So while some transistors might be 2 nm on a new process, others are largely unchanged from 3 or 5 nm. How much you get out of a new process is now highly dependent on how you design your chip and what you want it to do. This is why AMD is using multiple processes in a single CPU package these days. Some elements of their processors get little or no benefit from smaller nodes, so it's cheaper to make them on an older node.

adastra22 4y ago
I believe it doesn’t even measure that now. It’s pure marketing numbers, albeit industry wide instead of the fault of any one company.

Dalewyn 4y ago

>What does nm measure these days? Not Much.

imtringued 4y ago

It refers to the theoretical dimensions that a planar transistor would have to achieve the same density. Nobody uses planar transistors these days. Instead, 3d multi channel transistors are being used. The number is supposedly referring to the gate length of the theoretical planar transistor. If your transistors can reuse the same gate to drive three different channels, that means the effective gate length would be one third but once you open this can of worms, the numbers can be chosen arbitrarily to mean whatever you want.

Kye 4y ago
It's like knots. No one's dropping a knotted rope into the water to measure speed, but the term persists.