Microsoft’s Vista upgrade coupon scheme has arrived none too soon, it seems. A Goldman Sachs analyst quoted by the Taipei Times expects motherboard shipments to drop 4.2% from September to October, despite previously forecasting a 3.1% increase in shipments over the same time period. The drop is attributed largely to lowered demand caused by consumers and businesses holding off upgrades until the release of Windows Vista next January. According to the analyst, the decline in shipments occurred “earlier and more significantly than we expected,” and motherboard manufacturers may be left with oversupply as a result. The oversupply could trigger a price war as motherboard makers struggle to clear stock. Overall, the Gartner research group reckons Vista’s untimeliness may cut $4 billion from PC sales in 2006. Thanks to The Inquirer for the tip.