It wasn't a jump, more like a recovery.
AMD stock opened at 20.26, went as low as 19.08. After the quarterly results, spiked to 21.21 in after hours trading on 1/29/19. On 1/25/19 AMD stock closed at 21.93. AMD still hasn't recovered even from a few days ago.
Nvidia stock didn't do much better today. But did have an uptick due to AMD quarterly results.
Both are seen as tech stocks with similar product portfolios. So it's not strange if one is affected, both are affected. Nvidia's stock drop on 1/28 cause AMD's stock to drop as well. Today AMD's small uptick caused Nvidia slight uptick as well.