Mac Studio M3 Ultra 96GB vs RTX 4090D 24GB (China) for Local LLMs
The RTX 4090D 24GB (China) has about 23% more memory bandwidth (1,008 vs 819 GB/s). Batch-1 decode tracks bandwidth closely, so a model that fits both cards should decode roughly 23% faster on the RTX 4090D 24GB (China). The Mac Studio M3 Ultra 96GB fits more of the catalog at Q4/8K — 47 vs 33 of 61 models (96 vs 24 GB VRAM). Largest model that fits the Mac Studio M3 Ultra 96GB but not the RTX 4090D 24GB (China): DeepSeek-V4-Flash (158.1B). MSRP is $3,999 for the Mac Studio M3 Ultra 96GB vs $1,599 for the RTX 4090D 24GB (China). MSRP is a launch list price, not live retail — Amazon prices move; click through for the current price. Not retail-shoppable: RTX 4090D 24GB (China) (datacenter-class; cloud rental is the realistic way to use it). In the Q4/8K head-to-head below (47 shared models), the RTX 4090D 24GB (China) posts the higher tok/s in 37 rows vs 10. Methodology.