As the month of September draws to a close, some stocks have thrived, while others have fallen. But as investors, it's not so much the actual gain or loss that matters the most -- although it certainly matters somewhat -- but rather what drove that movement. This month the worst-performing tech stock on the Dow Jones Industrial Average (DJINDICES:^DJI) was semiconductor powerhouse Intel (NASDAQ:INTC), whose stock had retreated some 10% over the last 30 days at the time of recording. Watch on to see what drove Intel's nosedive this month.

Andrew Tonner has no positions in the stocks mentioned above. Follow me on Twitter at @AndrewTonner. The Motley Fool owns shares of Intel and Microsoft. Motley Fool newsletter services recommend Intel. Try any of our Foolish newsletter services free for 30 days. We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool has a disclosure policy.