The Broadcom SoC in the Raspberry Pi 4 (opens in new tab) Model B has been quietly updated to match the one in the Raspberry Pi 400 (opens in new tab), according to St Louis-based app developer (and more importantly, Pi Cast guest (opens in new tab)) Jeff Geerling.
Geerling noticed the change after buying a new Raspberry Pi 4, an 8GB model, to replace a broken board, and spotting that one character in the model number on one of its chips had changed. The BCM2711 (opens in new tab) is the SoC (System on Chip), the whole brain of the Raspberry Pi housing its CPU, GPU, and the PCIe link that connects the USB ports. Previously, its model number has ended in B0T, but Geerling’s new baby has a model number ending C0T, matching that used in the Raspberry Pi 400’s SoC.
It makes sense for Raspberry Pi to have done this, as it cuts down on the different chips they have to order and handle, and we can probably expect the new model to trickle down throughout the range — indeed, Geerling presents some evidence (opens in new tab) that this is already happening. The difference between the two models, however, is somewhat fine-grained. Extremely so, in fact. Highly granular, you might say.
It’s basically nothing. There are two main fixes related to RAM addressing, allowing the PCIe and EMMC2 buses to access more memory than they could before (hence why the new chip has appeared on the Pi 4 with the most RAM) and some ‘power gating improvements.’
The Pi 400 runs at 1.8GHz, compared to the Pi 4 Model B’s 1.5GHz, so the new chip may open up better overclocking potential, given sufficient cooling. Otherwise, unless you’re working on something that needs to access 8GB of RAM over EMMC2, it’s unlikely you will notice any difference.