I'm running an algorithm entirely from memory (no IO), yet my CPU use is below 25%. What may be the possible bottlenecks?

Question

I've been running a single-threaded brute force version of the famous Traveling Salesman Problem, and YourKit is pinpointing me the fact that the CPU is being used at 25%, at most.

What's the reason behind that fact? We've been told that these kind of algorithms are highly CPU intensive, yet there seems to be a lot of wasted CPU in this case.

My theory is the bottleneck must be the RAM access. Locking issues seem to be out of question, as the algorithm I'm running is single-threaded.

Am I right?