- The Special Value Pi 4 is a rare, binned version certified to run at 1.25 GHz instead of the standard 1.8 GHz.
- It was briefly listed by a reseller; the author bought two 4GB models for $160 total, including shipping and tariffs.
- Externally, the boards are identical to retail Pi 4s, but the 8GB model had an older B0 stepping and caused kernel panics at 1.8 GHz.
- One unit actually ran at 1.8 GHz, while the other required forcing to 1.25 GHz to boot stably.
- Power consumption at idle was unusually high (3W) compared to typical Pi 4s (<2W), due to voltage adjustments for lower-binned chips.
- A Raspberry Pi engineer explained that less than 0.01% of Pis fail validation and are sold to industrial customers at a discount, with DVFS normalizing performance across all chips.
- The article illustrates the silicon lottery and provides insight into parts binning behind the scenes.