
12.1 Technology and Architecture 941
faster with more storage, but it is still several chips with connectors and PC board
traces.
Indeed, from 1987 to 1997, the footprint of a basic processor and memory
module did not shrink much. There was an improvement from two nodes per board
to about four when first-level caches moved on chip and DRAM chips were turned
on their side as SIMMs, but most designs maintained one level of cache off chip.
Even if the off-chip caches are eliminated (as in the CRAY T3D and T3E), the pro-
cessor chip consumes more power with each generation, and a substantial amount
of surface area is needed to dissipate the heat ...