Semiconductor Economics

If the whole thing is mostly based on etched silicon shouldn't they be as cheap and common as CPUs? /s

It's probably a combo of cost-cutting and control. If you use a hardware chip, the chip itself only costs cents, but space is at a premium, and there assembly costs and reduced flexibility (you have to lock in your design well in advance).

Not really?The r&d isn't expensive because these are legacy/old type chips. There isn't much r&d happening. They're made using old processes.Any r&d is likely using different materials. Military stuff often uses different materials for specific applications.The profits come from raising yields, which is much easier on older nodes.

100% sure - once you have the masks, pumping out chips is cheap, if you do it in volume.http://www.adapteva.com/andreas-blog/semiconductor-economics...

Yes, you can fit more chips on lower nm, but you spend lots of money on tooling and suffer from lower yields compared to high nm processes. The cost of developing and tooling a modern, competitive ASIC, if you need a relatively modern process, can be tens of millions of dollars (not counting the IP development itself, just bringing to production).

Just curious, is there a high cost overhead (aside from the cost of actual units) of e.g. custom silicon?

You haven't been paying for the silicon for a while; when you buy a chip you're really paying for the design and it's cheaper to design one chip with all the features people might need.

Because a separate chip costs more.

Interesting! This could be read as:[Packaging separate dies, each made on distinct process] is cheaper than [use 1 process that is sub-optimal for big part(s) of the chip].Or: advanced IC packaging is cheaper than advanced semiconductor manufacturing.Still surprising this works for a <$1 chip. But makes sense considering what a new semiconductor fab costs nowadays.

Perhaps the cost of programming the smaller chips is high enough to offset it