Some other differences that are noteworthy ( doesn’t really apply to AI directly but perhaps how it is used in an AI workflow).
DGX Spark has one NVENC/ NVDEC chip. Thor has Two.
DGX Spark has a connect-x nic. Thor is not connect-x but a 4x25g nic. It doesn’t appear to support RDMA among other features you get with connect-x. which also means you probably can’t combine the thor modules very easily.
the different TFLOPS is interesting.