It turns out there are several solutions to this problem. A simple approach is to use the start command to launch each job with Low priority as follows

via Windows Tip: Launching a low priority process | ITworld.

I often find that processes that use the disk heavily for reading and writing tend to create the bottleneck. Even with RAID 0, 1, or 5, disk contention seems to be an issue. You can always throw more hardware at the issue, but you’d think software developers were a little more sensitive to how much CPU or lag a process uses. Sometimes you don’t want an application to run full throttle.