Nvidia has posted a warning yesterday, telling its investors it expects a 40 to 50 percent drop in Q4 revenue compared to Q3. What's worse, its Q4 revenue is usually higher than Q3, making the drop even more significant.

The graphics company blames weak end-user demand and inventory reductions by Nvidia channel partners in the supply chain. Apart from that, Nvidia's current graphics card lineup isn't holding up well against ATI competition, and the global economic crisis is seriously impacting demand in all market segments.

Nvidia's Q4 of fiscal 2009 ends January 25, 2009. The exact numbers will be available when Nvidia posts its financial results for Q4 on February 10th.

You can find the announcement here.