Yeah. There are workstations and workstations. Why would the original poster's single Haswell- or Skylake-based Core i7 CPU in his workstation waste more energy than a single Skylake-based Core i7 CPU on a new gaming machine? Also, his storage and GPU seemed quite modest, so I don't think his HP is more wasteful than a new gaming PC.

Of course, 28 cores and eight spinning hard drives is a different story.