The new dict implementation was introduced in 3.5 (with forced order randomization, which was removed in 3.6) because it is faster and uses less memory than the previous non-ordered dict. Ordering is merely a nice byproduct. So you're not paying any penalty.

OrderedDict is fundamentally different because it is designed to allow inserting/removing keys in the middle of the ordering in O(1) time. It does not use the new dict under the hood, or vice-versa.