yeah, so $500 spread https://www.microcenter.com/product/699008/nvidia-dgx-spark is what the current price appears to be.

The differences are basically, sparks require ARM and sparks allow interconnects; so if you do have dreams of electric sheep to chain them together, you're not gonna get the AMD halo units.

But if you just want to putz around with a dev machine and do other things, not sure you'd want a spark.