AMD announced its 6nm Ryzen 6000 'Rembrandt' APUs at CES 2022, a pairing of the Zen3+ CPU architecture and RDNA 2 graphics engine that appears so impressive that we named it the best GPU announced at CES. However, questions abound — could DDR5's eye-watering pricing and scarcity impact availability for the mobile parts, and when will we see these chips come to desktop PCs? It also remains to be seen if any AMD processors will support both DDR4 and DDR5, which could be a critical pricing consideration. I had the chance to sit down with AMD CEO Lisa Su and had a follow-up chat with David McAfee, the Corporate VP and GM of the Client Channel business, to learn more.
AMD's Rembrandt will undoubtedly challenge entry-level discreet GPUs in the laptop space, but given the ongoing shortages of GPUs for desktop PCs, we're just as excited to see those chips come to desktop PCs. However, AMD's APUs traditionally debut in laptops first then come to desktop PCs roughly a year later. AMD whittled that transition to desktops down to a record four months with Cezanne, so I asked if we should expect a similar cadence with Rembrandt.
"Paul, of course, I'm not commenting on future products that are announced at this point," McAfee said. "One of the dynamics that we do think about a great deal is how and when to introduce that AM5 ecosystem and ensure that the DDR5 supply, as well as pricing of DDR5 memory, is mature and something that's easily attainable for an end-user," he continued.
"And so there may be other forces beyond the product itself that slow down or meter the introduction of APUs into that AM5 socket. You know, we do expect that to be an enthusiast-first introduction. And I think we're going to have to watch very carefully just how the DDR5 transition takes place and how quickly both supply and prices come in line to make it more affordable for a mainstream consumer that might be more interested in making a product in that socket."
The AM5 socket for desktop PCs brings support for DDR5 and PCIe 5.0 to Zen 4 processors, but the news that the Zen 3+ Rembrandt chips will drop into AM5 shows that there is some room for a tweaked previous-gen architecture coupled with faster memory to make its way into the new socket. We also apparently won't see Rembrandt appear in desktop PCs with an option for DDR4 memory.
AMD has gone all-in with DDR5 memory with its Rembrandt chips. While DDR5 pricing could stabilize before AMD introduces the desktop PC AM5 platform, the company doesn't have that luxury with the laptop products — they come to market in February. I asked AMD if it felt that DDR5 could present supply or pricing issues with its Ryzen Mobile models in particular, or if it has plans to offer the chips with support for DDR4 memory, as Intel does with Alder Lake, to offer a lower-cost alternative.
McAfee said that AMD felt that DDR5 was the optimum choice to pair with the RDNA 2 engine, which makes sense given that the graphics engine will get a substantial boost from the doubled memory throughput. He also indicated that LPDDR5 modules don't have the 'same constraints' as DDR5 SODIMMs (the DDR5 shortage issue revolves around the small Power Management ICs present on standard DIMMs). The use of LPDDR5 could alleviate some of the pricing pressure, but, notably, Rembrandt-based laptops will also be available with SODIMMs.
"We've been working very closely with partners across the ecosystem, as well as our OEMs, to make sure that we're well-positioned from a supply standpoint to be able to satisfy the demand for DDR5 and LPDDR5 memory associated with our 6000 series," McAfee added.
In a conversation the day before, AMD CEO Lisa Su told me that AMD's AM5 socket for desktop PCs would soldier on as the leading-edge platform for quite some time, perhaps as long as the AM4 socket that is now entering its fourth year of service.
However, while we know that Rembrandt will only support DDR5, it remains unclear if AMD will have chips based on Zen 4 (or any other revision of Zen) that support both DDR4 and DDR5 in the AM5 socket. Timing a memory transition to coincide with affordable pricing is incredibly difficult, even in the best of times, and the ongoing global chip shortage was unforeseen a few years ago when AMD's chips were entering the design stages. Time will tell if AMD has made accommodations for DDR4, but that could be a critical factor if the DDR5 situation doesn't improve soon — Zen 4 is due in the second half of 2022. In either case, it's clear that DDR5 pricing and availability will impact the timing of Rembrandt's arrival to desktop PCs.