The sudden decline in new orders as evidenced by the plummeting of the chip book-to-bill ratio in January must have a string of over-optimistic chipmakers frantically redoing their sums before scaling back their investment plans. The slowdown surfaced at Cirrus Logic Inc rather earlier than for most of the rest of the industry, and yesterday it said it was reviewing its plan to process wafers at Digital Equipment Corp’s Hudson, Massachusetts facility in light of the current market conditions. Santa Clara-based Cirrus Logic warns of a fourth quarter loss.