Amazon is pretty clear that Gravatron is an actual core, while the others are hyper-threads[1]. It makes sense that at higher vcpu counts you're likely to run into contention with neighbors, or even yourself.<p>[1] <a href="https://docs.aws.amazon.com/whitepapers/latest/aws-graviton2-for-isv/optimizing-for-performance.html" rel="nofollow">https://docs.aws.amazon.com/whitepapers/latest/aws-graviton2...</a>