Nope. If a program is meant to run on the entire CPU, and if it's meant to use all the memory, then that's how it will run. This isn't a question of modernity

Nope. If a program is meant to run on the entire CPU, and if it's meant to use all the memory, then that's how it will run. This isn't a question of modernity or availability of tools or programmers' salary. Or, to put it differently, using more or less memory / CPU isn't really an indication of anything about a program. Sometimes you mean to use all that's available, other times you mean to use as little as you can. There's no way to tell which one should be done w/o knowing your goals. For example, the entire free memory on Linux is a free real estate for filesystem caching. So that memory is not wasted, if the system can help it. So, having your entire memory used (to support filesystem cache) wouldn't be really a performance problem (quite the contrary, it would look like the system is doing a good job at caching whatever reads your applications are making).