What is TDP (Power Draw)?
Thermal Design Power in watts — the maximum sustained power draw. Higher TDP generally means more performance but more heat and electricity cost. Important for 24/7 always-on setups.
Full Explanation
TDP (Thermal Design Power) specifies the maximum sustained power a component draws under full load, measured in watts. A 150W GPU running 24/7 draws ~3.6 kWh per day — about $0.50/day at $0.14/kWh (US average), or ~$180/year. A 20W Mac Mini M4 under constant load costs ~$17/year. For always-on AI servers, TDP directly determines your electricity bill. Discrete GPUs also require proper case airflow and may increase ambient temperature in small rooms.
Why It Matters for Local AI
For a dedicated home AI server that runs continuously, TDP is a first-order concern. The Mac Mini M4's 20W idle makes it the obvious choice for low-traffic personal use. The RTX 5070's 150W only makes sense if you're actively generating images or need interactive performance that justifies the cost.
Hardware Relevant to TDP (Power Draw)
mini-pc · Check Price on Amazon · 16 GB Unified · 120 GB/s
mini-pc · Check Price on Amazon · 16 GB Unified · 34 GB/s
accessory · Check Price on Amazon
Related Terms
Tokens/s→
Tokens per second — the standard speed metric for LLMs. One token ≈ 0.75 words. Above 10 t/s feels interactive; below 5 t/s feels like watching paint dry.
CPU Inference→
Running LLMs on the CPU rather than a GPU. Works on any hardware, no special drivers needed. Limited to ~8–12 t/s on 7B models — fine for background tasks, slow for interactive use.