The Santa Clara, California chipmaker said it would increase the size of the facility it is building in Vietnam from 150,000 square feet to 500,000 square feet and raise its investment from the $300m it announced in February to $1bn.

Five hundred thousand square feet is the optimum size based on multiple factors enabling us to increase our efficiency, said Brian Krzanich, general manager of Intel assembly and test. The Vietnam facility will be the model for larger, more efficient assembly and test facilities that will make Intel even more competitive.

The Vietnam facility will be the largest single assembly and test factory for Intel. Construction is slated for March and production is planned for 2009. The factory could eventually employ as many as 4,000 people, Intel said.

The Vietnam factory is part of Intel’s previously announced plan to spend nearly $6bn worldwide in capital additions, as part of its broader strategy to be more competitive.

Intel currently has test and assembly factories in Penang and Kulim in Malaysia; Cavite in the Philippines; Chengdu and Shanghai in China; and San Jose, Costa Rica.