Asus, Samsung and Dell are also experiencing "weak" sales of Windows 8 tablets, sources said. On Wednesday, Asus's chief finance officer, David Chang, revealed that "demand for Windows 8 is not that good right now".
Microsoft declined to comment on Surface. The company said this week it has sold 40m Windows 8 licences since the launch, outstripping sales of Windows 7.
guardian.co.uk © Guardian News and Media Limited 2010
image: © Nesster