GLM-5.3 320B (18B active) Flash

User reports GLM-5.3 Flash NVFP4 on two DGX Sparks at a 66.0 t/s mean decode across a task battery, with prefill at 1376 t/s on a 1.5K prompt. Setup is the GLM-5.3-Flash-NVFP4-DFlash2 recipe with DFlash2 speculative decoding, 3.55 of 8 draft tokens accepted per step, single request, and a KV pool of 560,362 tokens. Battery tasks range from 37.1 t/s on prose to 97.2 on bulk SQL inserts, and prefill holds near 1,576 t/s at 32K and 128K. The previous DeepSeek V4 Flash setup averaged 61.5 t/s on the same battery. A 40-minute soak at c4 served 503 requests with 0 errors at 83.6 t/s aggregate.