Summary
User reports DeepSeek V4.1-Flash decoding at a median 62.2 t/s on four DGX Spark (GX10) units in the original IKEA Kallax setup, with prefill of 4,255 t/s at 8K and 4,268 t/s at 250K.
Decode uses speculative decoding, which swings about ±10 t/s between runs, so decode was left out of the cooling comparison. Each run is a single 8-minute sweep from 1K to 250K tokens with the model already loaded.
Across six cooling setups the hottest GPU peaked at 82°C with no throttling; clocks stepped down about 3% from roughly 2525 MHz at 53°C to 2450 MHz at 82°C, and 250K prefill stayed between 4,225 and 4,353 t/s. The user's V3 open-faced air duct enclosure was the coolest setup at 65.1°C average under load.