Why? 4 x DGX sparks should be enough. That's way less than $80k.
For real work anything below 60 tokens per second is essentially unusable. That's not taking into account the prompt filling, Llama 3.1. 70b on DGX spark runs at about 800 tps running at that speed prompt filling a 512k context takes like 11 minutes.
To fit that model you'd need multiple machines which lets you run tensor parallelism for additional speedups, roughly X speedup for X machines. Also you can't naively compare tps across models, and it would certainly run a nvfp4 quant or similar.