Next-Gen PCIe 5.0 SSDs to Run Hot, May Require Cooling
SSDs that use the latest PCI Express 5.0 interface are expected to begin appearing sometime in 2022 (and beyond). That’s good news for fans of fast storage, as they offer double the throughput compared to PCIe 4.0. That means we’ll be seeing SSDs that can transfer data at a blazing 12GB/s, or thereabouts. The bad news is this new level of performance includes some heat-related concerns. After all, more speed equals more power, and more heat. This means that the next generation of SSDs will likely require cooling, which has never been the case previously.
In a a blog post from SSD controller company Phison, its CTO discusses the hurdles it’s facing with the heat generated by PCIe 5.0 SSDs. According to Sebastien Jean, Phison’s Chief Technical Officer, the company plans for its nex-gen SSDs to have the same thermal envelope as current drives. Jean says there are several strategies it can employ to achieve that goal. The most effective strategy is as old as time itself; moving to a smaller manufacturing node for increased efficiency. As an example, Jean describes moving from a 16nm node to 7nm. Another effective tool is reducing the number of lanes the SSD uses. In the past, more lanes was always better, but he says with PCIe 5.0 that’s not the case anymore. “In practical terms, you no longer need eight channels to saturate the Gen4 and even Gen5 PCIe interface. You can potentially saturate the host interface with four NAND channels,” he said. This reduction in NAND channels could result in up to 30 percent less power draw on the SSD.
One of the more interesting bits of information in the post relates to how an SSD dissipates heat. Jean says it does most of it by simply being bolted to the M.2 slot on the motherboard. (A modern SSD is installed by being pushed into an M.2 slot, then screwed down to the motherboard via a tiny screw and standoff.) Jean says removing heat is all about the conduction path, stating, “believe it or not, the little [M.2] connector that plugs into the board. Not super efficient, but it still contributes.” He also says the metal screw is responsible for 70 percent of the thermal conduction path. Despite this, some motherboard manufacturers have switched from metal screws to nylon fasteners. Though this solution is cheaper, it makes cooling the SSD more difficult. The other way SSDs dissipate heat is through convection. The SSD warms up and passes its heat to the air around it. This is where heatsinks, and eventually fans, come into play.
Jean says although the company is doing everything it can to reduce power consumption, it’s inevitable that future drives will require more advanced cooling. He likens the situation to GPUs, which first arrived with naked chips on a PCB. Next, they had heatsinks on some of the modules before eventually moving to active cooling with a fan. This is different than passive cooling, which only uses a heatsink. Thus far even PCIe 4.0 drives have managed being naked or with a thin heatsink, provided there’s good airflow inside one’s case. That won’t be the case for the next generation though. “I would expect to see heatsinks for Gen5,” he said. “But eventually we’ll need to have a fan that’s pushing air right over the heatsink, too.” We should point out that after this blog post came out Jean issued a correction to it, noting he was referring to enterprise drives only. He clarified that the company’s client SSDs will have the usual low-profile heatsink we see in current drives.
If you’re already starting to fret about how you’re going to cool your next 600W GPU along with your SSD, you can relax. Though PCIe 5.0 SSDs are supposed to arrive this year, all signs point to 2023 and maybe even 2024. Several of these drives have been announced, but they are all enterprise drives. Also, the only PCIe Gen 5 platform currently available is Intel’s Alder Lake. AMD’s upcoming AM5 platform will offer PCIe Gen 5 too, but that won’t be out until later this year.