Nvidia CEO Jensen Huang and AMD CEO Lisa Su.Tom Williams/CQ-Roll Call/Getty Images, Jerod Harris/Getty Images for Vox MediaAMD launched the Instinct MI325X accelerator on Thursday, and shipping starts later this fall.The new chip offers better performance than Nvidia's H200 yet lags behind Blackwell, analysts say.AMD's stock dipped over 4% post-announcement, reflecting only modest excitement amid competition.AMD CEO Lisa Su announced Thursday the launch of the Instinct MI325X accelerator, which is meant to compete against Nvidia.