QuickJS uses a bytecode interpreter (like Python, famously slow), and is optimised for simplicity and correctness. Whereas Deno uses a JIT compiler (like Java, .NET and WASM). Deno uses the same JIT compiler as Chrome, one of the most heavily-optimised in the world.

That doesn't normally lead to such a large factor in time difference, but it explains most of it, and depending on the type of code being run, it could explain all of it in this case.

QuickJIT (a fork of QuickJS that uses TCC for JIT) might yield better results, but still slower than Deno.