The G3440 is a pretty low end, dual core budget CPU. It’s not exactly gaming grade hardware. I can’t imaging that would perform too well with Rust in its current state of development.
That said, Rust is in alpha. Optimization is something that’s done in the final steps of development, not in early alpha stages. They need to get all the world, objects, graphics, features, etc into the game before they can even hope to start optimizing in any significant way.
I have no doubt that once Rust is a final, polished product, that it will be scalable to run well on a wide variety of hardware. But in the short term, you’re either stuck with the performance issues or you need faster hardware to run it.