The motion planning for the Universal Robot sometimes takes a couple seconds on my desktop and seems resource heavy

Are you referring to MoveIt here?

That's not "for the Universal Robot", but a generic motion planning stack.

I specified "Universal Robot", but perhaps should have referred to a "six axis robotic arm" as I figured the number of axes is a defining feature that affects motion planning.

While what you write could be true, my comment was more directed at the "the motion planning" part, which implies whatever specific setup / set of packages you're using now is somehow standard for a Universal Robot or any other robot.

That's not the case, and MoveIt itself can be configured in many different ways as well. Using Pilz' planner for instance would be a very different configuration than what most users will have, and will have a different performance profile (ie: OMPL (random guided search / optimisation) vs essentially 'simple' linear/circular interpolation). Even the choice of planner within OMPL itself (optimising vs non-optimising fi) has a significant influence on planning time and quality of plans.

If you're looking for suggestions on hw to use for certain use-cases, I believe it would be good to be as specific as possible about what you're using or intend to use. Hence my comment.

The question seems to be about MoveIt, but the title does not reflect that.

Thanks for your feedback. I am using Moveit. My kinematics solver is the KDL Kinematics Plugin. I was hoping to get some help on determining whether the hardware (Xavier) would be a limiting factor, and then improve my motion planning as necessary.

I have access to an Xavier so will just go ahead and run my project on there and try to optimize the Moveit configuration.