I have a 5600X and it's great for games. Actually AMD Zen 3 and Intel 10th or 11th gen are all going to be about the same in games because single core performance and IPC matter more. However, in productivity tasks like video encoding and rendering, more cores are better so Zen 3 has the advantage with the 12 core 5900X and 16 core 5950X.
Also AMD CPUs use less power because they are 7nm, which means less heat so they can run at boost clock frequencies for longer. However, the Alienware case and their graphics card coolers are notoriously bad so you might want to upgrade those first.