Intel has been at 22nm for a while now, TSMC and other foundries are expected to ship the first high-performance 20nm products next year, but Nvidia thinks going beyond 20nm won’t be nearly as smooth.

Speaking at IEF 2013, Nvidia researcher John Chen said transistors at the sub-20nm level will have to employ tricky design rules and face new challenges. These problems could have a negative effect on yields, pushing the wafer cost up, while at the same time dragging yields down.

That’s why Chen believes 450mm wafers are long overdue, because they are one of few ways, if not the only way, to reduce wafer and die cost. According to TechEye’s Mike Magee, Chen also sees zero leakage transistors, carbon nanotubes, and III-V/Ge as technologies that could help the industry tackle sub-20nm challenges.

Here’s an interesting number shared by Chen – Nvidia’s massive GK110 has the equivalent of 20 kilometres of metal length in it.