Nvidia had already prepared the high-end GTX 780 Ti graphics card to counter AMD's line of R9 graphics cards, PCR has learnt.
Sources say that Nvidia was just waiting for AMD to announce its cards before it revealed the 780 Ti.
"To come out with a card so quickly after the R9 cards were announced is impossible," a senior source told PCR. "So Nvidia knew about AMD's plans for the 290 in advance - they were just waiting for the right time to announce it.
"I doubt AMD have anything else planned at this stage, I think they can only drop prices."
Nvidia is also said to be announcing the specifications for its new high-end GeForce GTX 780 Ti graphics card this week, and it will "definitely outperform" its rival AMD Radeon R9 290X.
According to Videocardz.com, the 780Ti will be faster than the 290X (and the Nvidia Titan), which the official specs should confirm that this week.
Nvidia has already announced its GeForce GTX 780 Ti will be available for sale starting November 7th for $699, and says the card is the best its ever built.
"It's a phenomenal card, and will definitely outperform AMD's 290X," our source added.
An Nvidia spokesperson told PCR that Nvidia doesn't comment on rumour or speculation.