DGX Spark has a maximum of 273 GB/s bandwidth in ideal scenarios (hard to reach)
That puts it between an M5 (153) and M5 Pro (307)
Mind you thats not to/from memory, which indeed only has 273 GB/s.
Perhaps a sobering rule of thumb: if it was actually useful, you couldn't buy them because someone would scoop them all up to shove them in a DC and make money with it.