Large models where the interesting work is the system around the weights: topology, kernels, memory, speculative decoding, serving and the point where a nominally healthy lane actually fails.
3–4× DGX SparkKimi K3 Neuron
The public bring-up package documents the Neuron IQ1_S GGUF running end to end across three and four Sparks, including local-NVMe loading, NCCL fabric receipts and the TP geometry. The 3-Spark path uses 512/512/512 FFN-width shards; the recipe also records why raw token-ID speed prompts are not quality tests.
Model ~330 GB GGUFEngine SparkInferTP3 6.21 tok/s best published windowScope public recipe snapshot
2× DGX Spark428B
The model loads on the tempting b12x path and even returns healthy API status, then the first real request kills the engine because the TMA attention kernel cannot JIT on the stock CUDA-13.0 driver. The working answer is a different lane, not driver surgery.
Standing lane KVarN + EAGLE-3Code 34.0 tok/sStructured 41.1 tok/sDeep run 17.8 tok/s @ 113K
2× DGX Spark295B MoE
Dual-Spark Hy3 serving with NVFP4 W4A16, native MTP, FP8 KV cache and structured tool calling. The campaign measures both speed and an accuracy slice, because a quant that serves quickly but damages the model is not a successful deployment.
Single 13.1 tok/s6-way 36.9 tok/sGSM8K slice 98.7%MMLU slice 90/100
2× DGX SparkDeepSeek V4-Flash
A live TP2 lane became a systems study: MTP acceptance by task family, reasoning-field behaviour, cache effects and long-context retrieval. The server advertises a 1M window, but the checkpoint is trained to 65,536 and cold retrieval becomes unreliable rather than failing cleanly.
Serve 1,048,576 max-model-lenTrained 65,536Soak 10.20 hRequests 2,400/2,400 HTTP 200