meta released muse spark open weights on oct 15: 816b total, 42b active, 1m context. the nvfp4 checkpoint is about 530gb, a third of the 1.6tb bf16 weights, and only the experts are quantized. meta says it serves on four blackwell ultra gpus or two 512gb m5 ultra mac studios.
Build with Muse Spark Open
dev.meta.ai