It's hard to compare Rust or C++ to GC langs like C# and Java because their runtimes are greedy. The CLR will easily take 10x more memory than it's currently using such that future allocations are much, much faster. So measuring the memory consumption of a JVM/CLR application is not simple. You need to ask the GC how much memory you're actually using - you can't just check the task monitor.

Also you can do that same thing in Rust or C++ too. Very common in C++, speeds up programs quite a bit.