Wait, are people taking the UFS card idea seriously?
Nintendo makes some funky moves, but a dead (well, never alive really; failed) format being required for the next system, a system which at launch will primarily just play existing games better?
If they adopt UFS card I will eat a shoe.
I fully expect them to stick with SD... Not least because they're part of the SD consortium, but also because of backwards and forwards compatibility. I don't think the Drake Switch could really insist on a new format, but maybe the one after it. If and when they move to a new storage expansion format, there's little to no reason for them not to go with SDExpress. The power consumption is higher than SD, but it fits within Switch's power constraints with an absolute max of 1.2W, but which can be driven far, far below that. The price consideration isn't a considerable issue, the price will come down with enough time, just like 256GB and 512GB Micro SDXC before it. There simply isn't a reason for them not to go straight down the line of "whatever minimum SD card speed works".
UFS? Sure. UFS Card? Absolutely not.
The drawbacks are pretty severe; lack of existing production capacity.
Lack of software, hardware, and vendor support.
Lack of economies of scale (comparatively).
Lack of input from Nintendo.
Nintendo quite literally sits on the board of SD. Why would they abandon their own product in favour of a competing, dead format?
While SDExpress might have its disadvantages, they don't outweigh the advantages. Nintendo had a say in developing the spec to begin with. It can use lower power consumption if it sacrifices speed, something Nintendo is familiar with, and even if they don't it can, technically, fit within the power envelope of even the existing Switch.
Also saying readers CAN support both. But have any been made? Will any ever be? Given how hard it flopped, I'm doubtful.
The reason we're talking about UFS cards is that, if Nintendo want to ensure games have a significantly faster baseline storage speed than UHS-I SD cards provide, they'll have to go with either SD Express, CFexpress, or UFS cards. I personally think UFS cards would be the best choice, but that doesn't necessarily mean that I think they will use UFS cards, or even that they'll necessarily use anything better than the same UHS-I microSD cards used in the current model, but this is a speculation thread after all, so it's interesting to speculate.
Out of the three options, I'm increasingly of the opinion that pretty much the sole advantage of SD Express is that is says SD on it. Unlike CFexpress and UFS cards, there hasn't been a single device yet released which supports SD Express, and there's very little indication of any future devices that will. Its primary market was intended to be in cameras, but the high end of the industry has already moved fully to CFexpress, and SD Express isn't backwards compatible with the UHS-II SD standard used in many mid to high end cameras, so there's little reason for any camera manufacturer to adopt it. As an example, Sony's $4000 a7R Mk V was announced the day before yesterday, and SD Express support is nowhere to be found on it. It supports CFexpress Type A and UHS-II SD cards (in fact they ironically use a CFexpress/UHS-II SD combo slot that provides better backwards compatibility than an SD Express slot would).
The limited (or zero) adoption of SD Express is a much bigger issue than it is for the other two formats, because the SD Express interface is a combination of the original SPI SD interface, the UHS-I SD interface, and an NVMe interface alongside those. Because of the need to support all three of these interfaces, SD Express cards require custom controller/interface chips, and therefore they can't leverage existing economies of scale in the same way that UFS cards can with eUFS, or CFexpress can with NVMe SSDs.
While the SD Express specification states a maximum power consumption of 1.2W, there's no indication they're actually enforcing that. The only publicly available power measurement of an SD Express card that I'm aware of
showed an average of 3.25W power consumption, peaking up to 4.58W, and with surface temperatures of up to 96C.
The benefit of UFS cards is that being based on the existing, widely used UFS interface means the following simply don't matter:
lack of existing production capacity.
Lack of software, hardware, and vendor support.
Lack of economies of scale (comparatively).
To illustrate my point, when
comparing the price of UFS cards and the similarly niche UHS-II microSD cards earlier this year, the UHS-II cards were being sold for 50% more while operating at half the speed. Even for the tiny production runs Samsung would have been doing on these UFS cards, being able to leverage the enormous economy of scale of eUFS counted for a lot more than the economy of scale of any post-UHS-I SD standard. Hardware and software support is also a moot point, as any SoC that can support eUFS can also support UFS cards, as they use the same M-PHY/Unipro interface (only with one lane instead of two). Ditto with software support, although in Nintendo's case they'll be implementing that themselves, so not really an issue.
More importantly, though, the power consumption of UFS cards should be much better than SD Express, again because it's leveraging existing eUFS technology. I haven't been able to find any real-world power figures for UFS cards, but embedded UFS is designed primarily around maximising performance in very tight power limits, given its use-case in smartphones, so power consumption should be low and well-controlled. When you're an embedded memory supplier selling to the smartphone market you can't really get away with exceeding the power and thermal spec by a factor of 3, unlike if you're developing custom controllers for memory cards where the purchaser will be unlikely to even consider power consumption. Utilising existing eUFS controllers in UFS cards hence means it should have much better and more reliable power consumption than SD Express.
CFexpress is also worth mentioning, and does have a few advantages. Firstly there's actually an existing market for them, although it's the niche, expensive world of high-end cameras. It's also effectively just an NVMe SSD in a plastic case, so much like UFS cards it can leverage existing economies of scale. While current cards are very expensive, I suspect that's largely due to the fact that the current target market is pretty price-insensitive. The Xbox Series X/S storage expansion cards are slightly modified CFexpress Type B cards, and cost about half as much as a CFexpress Type B card would at the same capacity. The Xbox expansion cards are also a proprietary accessory, so there are probably pretty healthy margins on it, and I expect competition could push prices down even further.
CFexpress Type B are a bit large (and overkill performance) for a device like the Switch, but the smaller Type A card would be a good fit (they're about the same size as a Switch game card). They also hit a baseline of 800MB/s read speeds, with Drake potentially being forward-compatible with future 1.6GB/s PCIe 4.0 cards. Of course the fact that it's just an NVMe drive in a plastic case is also the problem, as the specification doesn't seem to put any limits on power draw. The only measurement I could find for power consumption of a CFexpress Type A card is
this one, which specifies <1.7W active power draw on its spec sheet. That's about half of the SD Express card, but potentially still too much for a device like the Switch. There's also no indication of whether this is typical for CFexpress type A, or if other cards could pull a lot more power.
There's a tendency to think that, because SD cards have been around for so long, the best option will inevitably be whatever the latest SD card is, but that's not really the case anymore. The last SD card standard to achieve mass market use is the UHS-I standard that was published back in 2010. The UHS-II standard has seen limited, niche use, the UHS-III standard was never used, and the SD Express 7.0 and 8.0 standards have yet to see support in any devices (although one or two cards and readers exist). The Frankenstein approach the SD association have taken to backwards compatibility hasn't helped, as they've just kept tacking on different interface specifications over the years. SD Express cards have to implement backwards compatibility with the 1-bit SPI mode that originated on the MultiMediaCard standard back in 1997, but can't support the UHS-II or UHS-III standards that actually precede it. In comparison, the Compact Flash Association have been happy to drop old standards to keep both cards and readers simple and utilise standardised technologies like SATA and NVMe, and that's surely been a factor in their newer standards actually being adopted, rather than left on the shelf.