DSOGaming writes: “Ubisoft has released a new patch for the PC version of Assassins Creed Odyssey. This patch will update your games version to 1.03 and it appears that it has a fix for the processors that lack AVX support. In other words, those with Intels first generation CPUs (and other CPUs) will be able to launch and play the game.”
Source: N4G PC Assassin's Creed Odyssey PC patch 1.03 available for download, resolves the AVX CPU issues