Raspberry Pi Tweaks the Raspberry Pi 4 to Support Two RAM Chips As It Fights AI Bubble Parts Pricing
Unceasing demand for DRAM components from the AI industry has Raspberry Pi scrabbling for cost savings in its latest PCN.
Raspberry Pi has quietly launched a new variant of its last-generation Raspberry Pi 4 Model B single-board computer, which offers support for using two dynamic RAM (DRAM) modules instead of one — a direct response to the ever-increasing cost of high-capacity DRAM chips that has driven two price hikes in the last two months.
"Product Change Notification: Update of Raspberry Pi 4 Model B (all variants) PCB to support dual DRAM modules," a document released to partner companies explains of Raspberry Pi's latest hardware design change. "The PCB has been revised to include a second site for DRAM placement on the rear of the board, and to allow for intrusive reflow soldering during manufacture. Reason for Change: Dual DRAM device variant to allow DRAM supply chain flexibility. Manufacturing process improvement (this new revision uses intrusive reflow soldering)."
The move to intrusive reflow soldering is of little impact to end-users, but the bigger news is the move to allowing for either one or two DRAM modules to be fitted — a first in Raspberry Pi history, with the range having originally started with a stacked package-on-package module that saw the DRAM sited on top of the Broadcom system-on-chip to which it connected.
The reason for the change: the artificial intelligence (AI) bubble, which has spiked and continues to spike DRAM component prices — with industry analysts suggesting that the next quarter could see another near-doubling in spot pricing. The insatiable demand for memory from the AI industry has seen Raspberry Pi forced to increase the pricing on its most popular products twice in the last two months with more price hikes expected to follow over the course of the year. With the option to place one or two DRAM modules on each board, Raspberry Pi gains the flexibility to use modules of half the capacity to deliver the same amount of RAM — buying in whichever is the most cost-effective at the time.
It's a tried-and-test approach: Sinclair's classic ZX81, a cost-reduced minimum-chip-count successor to the ZX80, featured the option of installing either one 1kB or two 512B memory chips depending on what was available at the lowest price at the time — though the capacities Raspberry Pi is dealing with are, thanks to the inexorable march of technological progress, orders of magnitude higher.
"Some tasks will perform slightly better, some will perform slightly worse, depending on the memory access patterns," Raspberry Pi's principal software engineer James Hughes predicts of the impact the change will have on overall system performance. "On average, performance is the same, or at least, so close that it make no real difference except in pathological benchmarks."
The new boards will begin to appear at resellers in the near future, but buyers won't be given the choice of whether they get single- or dual-chip designs. No similar change has been announced for the current-generation Raspberry PI 5, though it seems likely the same engineering work is underway there too.
More information is available in the parts change notification PDF.