If you bought it for inference you made a mistake. They aren't good at that. Use it to train models and experiment with ML. It's much better at that.

If you just want local inference buy a Mac.

If you bought early on, like I did, the Spark is probably worth double what you payed now. I think I paid $3,000 retail for mine and the last time I looked they were fetching close to $6k on ebay. I'm not sure if that's still the case, but you can buy a very nice Mac with $6k.