NVIDIA’s new FP4-Local checkpoint re-quantizes GLM-5.3-Flash with quantization-aware distillation and compressed expert scales, cutting it to 164.6 GiB with near-baseline accuracy — but it requires a forked vLLM stack (B12X kernels, modelopt_mixed loader), and the checkpoint’s own author says 4× Spark clusters gain little from it: the quant exists to buy back KV cache on 2-node setups, a constraint four nodes don’t have.