At 32,000 tokens, the costliest thing my MacBook did was wait seven minutes to speak

I ran the same long-context test on a 16 GB fanless M3 and a ₹23 rented NVIDIA L4. The laptop fits a 32k context on an 8B model and keeps every planted fact — but prefill balloons to seven minutes and its decode speed can't even be measured, because the fanless chip throttles. A measured, cross-hardware look at the KV-cache tax.