4 ms·

> The meaningful achievement is how many discrete electrical components are composed into a given area. Is average over an area the meaningful achievement or i

> The meaningful achievement is how many discrete electrical components are composed into a given area. Is average over an area the meaningful achievement or is the meaningful achievement the smallest individual gate length? Neither are super useful without additional context.

hinkley 6y ago
Let's say I made a tiny transistor but to avoid leakage/interference or melting the transistor, I had to surround it by a bunch of empty silicon. There are lots and lots of cases where this could not be called a success. I hesitate to say there are none, because I'm sure some task that is highly sensitive to latency might potentially benefit, but if you build the whole chip that way, it would actually be a regression.
- eightysixfour 6y ago
  Sure but, despite the extra space around any individual transistor, you're still shoving 49% more transistors into the same overall amount of space. Then everything benefits and no one cares about the node name.
  - hinkley 6y ago
    > you're still shoving 49% more transistors into the same overall amount of space What I fear is that we've hit the point where this is no longer a safe assumption. That we will be having people chase feature size numbers that don't actually result in a proportional increase in chip density. Transistors per square millimeter is closer to a measure we actually care about (speed of light and clock speed) instead of a bench number that doesn't measure anything except perhaps instructions per watt.
    - eightysixfour 6y ago
      What from the article makes you think that's no longer a safe assumption? The 49% gain is exactly what happened going to 5nm. I don't think anyone actually cares about transistors/mm^2 at all, I think what we care about is perf or perf/watt for our specific workloads. I don't care if the chip is built with vacuum tubes if it is fast, efficient (per dollar and watt), and physically fits in the device I want it in.
      - hinkley 6y ago
        First, because TSMC was aiming for 1.8x and Apple only saw 1.49, and I expect that not to improve going forward. Second, one of us is reading that number wrong. They said 1.49x, not 49%. In any other conversation, 2x is reducing feature size by 50%. 3x is 1/3 of the original, or reduced by 2/3. That means 1.8 is 45% smaller, and 1.49 is 32.9%. Similarly, if you cut the pitch of a circuit in half you should see 4x as many transistors. If you could keep shrinking the space between transistors while shrinking the transistor, then going from "7" to "5" node should have been a 1.96x factor for areal density, not the 1.8x they claim, or the 1.49x Apple achieved. I'm not saying they screwed up. As soon as nodes stopped measuring literal transistor size, it wouldn't take long for the names to be aspirational instead of descriptive. It's something they can name the project early on when the set of potential tech has been selected and some estimates have been made. For building a team it's fine. But I'm not on that team, I'm a customer (and current or former shareholder). I think the consumer cares about the transistors per mm^2 (after the voltage and the instructions per second), not the node number. Especially when each foundry uses the same number to describe different densities. I shouldn't have to keep remembering that TSMC-7 = INTC-10. Numbers that are actual numbers, please.

hinkley 6y ago

Let's say I made a tiny transistor but to avoid leakage/interference or melting the transistor, I had to surround it by a bunch of empty silicon. There are lots and lots of cases where this could not be called a success. I hesitate to say there are none, because I'm sure some task that is highly sensitive to latency might potentially benefit, but if you build the whole chip that way, it would actually be a regression.

eightysixfour 6y ago
Sure but, despite the extra space around any individual transistor, you're still shoving 49% more transistors into the same overall amount of space. Then everything benefits and no one cares about the node name.
- hinkley 6y ago
  > you're still shoving 49% more transistors into the same overall amount of space What I fear is that we've hit the point where this is no longer a safe assumption. That we will be having people chase feature size numbers that don't actually result in a proportional increase in chip density. Transistors per square millimeter is closer to a measure we actually care about (speed of light and clock speed) instead of a bench number that doesn't measure anything except perhaps instructions per watt.
  - eightysixfour 6y ago
    What from the article makes you think that's no longer a safe assumption? The 49% gain is exactly what happened going to 5nm. I don't think anyone actually cares about transistors/mm^2 at all, I think what we care about is perf or perf/watt for our specific workloads. I don't care if the chip is built with vacuum tubes if it is fast, efficient (per dollar and watt), and physically fits in the device I want it in.
    - hinkley 6y ago
      First, because TSMC was aiming for 1.8x and Apple only saw 1.49, and I expect that not to improve going forward. Second, one of us is reading that number wrong. They said 1.49x, not 49%. In any other conversation, 2x is reducing feature size by 50%. 3x is 1/3 of the original, or reduced by 2/3. That means 1.8 is 45% smaller, and 1.49 is 32.9%. Similarly, if you cut the pitch of a circuit in half you should see 4x as many transistors. If you could keep shrinking the space between transistors while shrinking the transistor, then going from "7" to "5" node should have been a 1.96x factor for areal density, not the 1.8x they claim, or the 1.49x Apple achieved. I'm not saying they screwed up. As soon as nodes stopped measuring literal transistor size, it wouldn't take long for the names to be aspirational instead of descriptive. It's something they can name the project early on when the set of potential tech has been selected and some estimates have been made. For building a team it's fine. But I'm not on that team, I'm a customer (and current or former shareholder). I think the consumer cares about the transistors per mm^2 (after the voltage and the instructions per second), not the node number. Especially when each foundry uses the same number to describe different densities. I shouldn't have to keep remembering that TSMC-7 = INTC-10. Numbers that are actual numbers, please.