Since When Did My SSD Need Water Cooling?

Feature As the latest generation of M.2 SSDs have trickled out to consumer platforms we've seen some wild and wacky cooling solutions strapped to them: heat pipes, 20,000 rpm fans, and even tiny liquid coolers.

Perhaps the most extreme example we've seen so far is Adata Project NeonStorm. It packs a self contained liquid-cooling system, complete with pump, reservoir, radiator and pair of fans to the the gum-stick-sized drive. However, it is hardly the only one. TeamGroup and Inland have also strapped fans and even whole cooling towers to their SSDs.

But are PCIe 5.0 SSDs so hot they need active cooling or are all these fan-strapped SSDs just a gimmick playing on gamers' ignorance or irrational love of unicorn barf? Oh, did we mention many also have RGB?

Adata's XPG NeonStorm SSD features an all-in-one liquid cooler (click to enlarge)

In a blog post containing very little specifics, Adata makes the case that traditional passive heat dissipation is inadequate to meet demands of PCIe 5.0 SSDs and that some kind of active heat dissipation is now a requirement.

Micron's Jon Tanguy, who works on SSDs under the company's Crucial product group, isn't so sure. He tells The Register that while it's true that the latest generation of SSDs really are running hotter, Crucial doesn't yet see the need for active cooling for its drives. 

Faster NAND is hotter NAND

With each subsequent PCIe generation, bandwidth per lane typically doubles. With PCIe 4.0 SSDs, we were closing in on the theoretical max of 8GBps. Today, a PCIe Gen 5.0 x4 SSD is capable of anywhere from 10-14GBps once you factor in the litany of bottleneck and storage overheads.

The amount of activity taking place on the gumstick-sized M.2 form factor means higher temps not only for the storage controller, but for the NAND flash itself.

NAND, Tanguy explains, is happiest within a relatively narrow temperature band. "NAND flash actually likes to be 'hot' in that 60° to 70° [Celsius] range in order to program a cell because when it's that hot, those electrons can move a little bit easier," he explained.

Go a little too hot — say 80°C — and things become problematic, however. At these temps, you risk the SSD's built-in safety mechanisms forcibly powering down the hardware to prevent damage. However, before this happens users are likely to see the performance of their drives plummet, as the SSD's controller throttles itself to prevent data loss.

The latter is one of the reasons why even during the PCIe 4.0 generation it wasn't uncommon to see aluminum or even copper heatsinks sold alongside premium models.

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The takeaway is that with PCIe 5.0 SSDs — the performance oriented models in particular — some kind of cooler is necessary to achieve peak performance. Whether it needs to be actively cooled is another question entirely.

Crucial's upcoming T700 SSD, for example, is being marketed with a passive heat sink preinstalled. The company will sell you a version without the heat sink, but this is for customers that want to use their motherboard's built in heatsink or a 3rd-party one. Tanguy emphasizes that a cooler is still needed.

As long as there's adequate air flow over the drive, Tanguy and his team don't see the need for active cooling, at least with this generation of SSDs.

"We decided from our standpoint that the addition of active cooling was probably more than our customers would want to do," he said.

With that said, Tanguy expects this to be a particularly challenging problem to solve as PCIe 5.0 SSDs make their way to the notebook segment, where the options for airflow are limited.

More points of failure, and worse capability

The good news is strapping a fan or liquid cooler to an SSD realistically isn't going to hurt anything, other than maybe your wallet. "I don't want to sit here and say all of these things don't work because they likely will," Tanguy said of actively cooled SSDs.

While NAND flash tends to prefer higher temperatures there is nothing wrong with running it closer to ambient temperatures, Tanguy said.

In this humble vulture's opinion, strapping active cooling to an SSD is a bit like using a massive dual-tower cooler or 360mm radiator to cool an Intel Celeron. It's not going to hurt anything, but it's also not going to make much, if any, difference in terms of performance, and it's going to cost you far more than a more appropriately sized cooler.

Remember under peak loads, these SSDs are pulling at most 11.5 watts, and because of the M.2  form factor, maintaining a sustained load isn't trivial. The transfer rates you see listed on most consumer SSDs are for relatively bursty workloads. Once the SSD's DRAM and/or SLC caches fill up, transfer rates typically fall to a fraction of what's claimed. As a result, it's unlikely the drive will be running at full load for any extended period of time.

But even though active coolers won't hurt anything, that's not to say they can't cause problems when it comes to reliability or compatibility. According to Tanguy, with each moving part you add to a storage system, you introduce another potential point of failure.

"We spent a lot of years taking moving parts out of the storage systems to get to this point now where we're putting moving parts back in, just to make it more likely to fail or get noisy," he said.

Imagine the racket a 20,000 rpm fan might make when its bearing starts to fail a few years down the line.

Then there's compatibility. Many motherboards today feature integrated heat sinks for M.2 SSDs. Taking advantage of something like Adata's Project NeonStorm liquid cooled SSD will likely mean forgoing that.

There's also the potential for these SSD's larger coolers to interfere with other components, like CPU tower coolers or GPUs. This is because the majority of PCIe 5.0 slots are located just below the CPU socket to minimize trace length to ensure signal integrity.

So, do you really need a liquid cooled SSD? Probably not, but if you want one anyway, we can't say we blame you. ®