> Sophie Wilson has said that cost-per-transistor is rising since we shrank below 22nm

The data has been saying otherwise. 5nm is the only node that increased $/transistor beyond it's previous node (7nm), and that's at a time when Apple payed out the ass for a monopoly on the node except testing shuttle runs from competitors but isn't a sign of a fundamental increase in cost.

https://cdn.mos.cms.futurecdn.net/Unwdy4CoCC6A6Gn4JE38Hc-970...

> and that a 7nm die cannot run more than half of its transistors at the same time without melting.

That's true for trying to run multiGhz designs in classic plastic package BGAs like most cell phone chips, but that's been true for a while, hence why flip chip packages are a thing. Actually having a heat spreader connected to the die goes a long way.

Wilson's comments aren't incorrect from a certain point of view, but tend to get extrapolated out of her niche to the greater industry in a way that pushes the statements into inaccuracy.

Thanks, the cost per wafer does look convincing. I wonder where Wilson's figures emerged.

I think what's happening is that initially a node is more expensive, because of consolidation of the market and supply/demand amongst all of the fabless customers until capacity fully comes up. Once we're back into steady state we see the traditional economics of $/transistor falling.

That sort of coincides with TSMC having competitive, close to leading edge nodes (so the 28nm timeframe) which would line up with the rumor. The information simply hasn't been updated over the timeframe of the node. Previous to that the cost of the node was pretty fixed as long as someone like ARM cared about, now there's a lot more economic effects from the increased buyer competition that heavily changes final cost over time.

I believe her talk was from late 2017, so 7nm would have been expensive.

At the same time, AFAIK Intel was doing quite well at 14nm finfet even then (likely better than any other foundry?), but that production capacity was not available to ARM, so I guess it didn't count.

Yeah exactly. I want to be clear, I've got a tremendous amount of respect for Sophie Wilson; she's a much better engineer and more connected to how the industry is going. Her statements simply require a lot more caveats than they are normally given. It's more about the much the changing position of ARM and TSMC in the market place than anything else.

> At the same time, AFAIK Intel was doing quite well at 14nm finfet even then (likely better than any other foundry?), but that production capacity was not available to ARM, so I guess it didn't count.

Yeah, and Intel was right in the middle of their biggest misstep. Intel 10nm was in risk production for Cannon Lake with awful yields and therefore a huge $/transistor. It got shipped anyway as one SKU in May of 2018 that didn't make financial sense (there's rumors that management bonuses were tied to that release), before being relegated to process improvements for years until just recently.

It would have been fair for her to extrapolate a trend there that actually ended up being more complex in hindsight.

Anecdotally, I recently had a CPU fail for the first time and it was a 7nm one. Sent it to AMD, they verified the failure and sent a new one back. Meanwhile I have had assorted 22nm/14nm processors around the house chugging along for years without any issues.

This problem is not specific to Intel. Many chips are not using the smallest node sizes and old fabs get a second life producing those chips instead of CPUs. That could soon be the future for Intel fabs.

That's where a fab goes to die. It needs to be fully capitalized at that point or else you don't have the money for R&D on leading edge. Intel going this direction is the direction of GloFo and no longer even attempting leading edge node production in the US anymore.

We're going to need stuff like processors with built-in microfluidic cooling layers. Why not have club sandwich construction with every other layer working on heat extraction, power, or both? I see a future with cube-shaped processors with hundreds of layers.