AMD laid off 600 people in the fourth quarter of 2008, rather than the 500 it expected to let go.

Severance payments and other benefits will cost the chip maker $34m, $13m will be spent on ending contracts and programs, $17m has been written off the value of its assets and $6m will be spent on closing factories and offices. In total AMD told the Securities and Exchange Commission it will spend $70m rather than the expected $50m on its cost-cutting plan.

There will be further charges in the first half of 2009 but AMD doesn't yet know how much these will cost.

AMD said it was writing down the value of the goodwill connected to its acquistion of ATI in 2006 in light of its falling share price. The company will work out how much this has cost it and tell the SEC if it is a material charge.

AMD's SEC filing also revealed it is writing off $20m relating to its investment in Spansion. ®