(Part 11 in a series of posts on small-form-factor computing)
Before I temporarily ended my series on thresholds in small-form-factor computing, I talked about Thin-ITX being the last stop in a series of miniaturisations. For a while it looked like the Intel NUC might become the next form factor; there were third-party cases and coolers being made for it, and Intel has stuck with it for three generations, gradually lending it the stability needed for OEMs to build businesses around the product. Nobody wants to make accessories and alternative parts for something that could disappear in
a year or two.
But in CES 2015, something interesting appeared: a socketed sub-ITX motherboard.
Not quite as tiny as the NUC, but it has one advantage over the NUC: it supports socketed CPUs just like their larger brethren, and up to a TDP of 65W. This means that it has a higher performance ceiling than the NUC, which is limited by its small size. A smaller case cannot fit as much cooling hardware, and will run into performance limitations due to the operating temperature limit of processors.
Late last month, this new product was christened: it is named the 5×5. How did it manage to further shrink Thin-ITX, which already had things crammed into every bit of available circuit board space? Anandtech’s coverage has a handy comparison image with Mini-ITX, but which is unfortunately missing Thin-ITX.
Until more details are known, it is hard to say for sure what has disappeared and what hasn’t. But some things are immediately apparent:
- SATA ports for storage devices take a backseat. There is only one seen in the display unit from Intel, and yet no connector for SATA power. M.2 is expected to be the main storage interface for 5×5.
There is no PCIe slot. Not even an ×1 slot. This may seem to limit the potential of the 5×5, and if we are speaking only of functionality provided by add-on PCIe cards, that certainly is the case. But the 5×5 has M.2 slots for add-on cards in addition to the storage drive, so it’s not like it has completely lost all expansion capability. This allows the board dimensions to shrink from 17cm to 13cm (7″ to 5″) as well, since the full-length PCIe slot is almost 10cm long, not including the spacing around it that is mandated by the form factor.
There is no platform controller hub (PCH) visible. The PCH is responsible for communication between the CPU and peripherals—the storage devices, network card, audio chip, and so on. That might not mean it is entirely gone; it could be hiding on the other side of the 5×5, or perhaps integrated into the CPU in future iterations, but this is a good sign. In Part 9 on heat dissipation, I mentioned that the PCH is one source of heat inside the case that can really raise temperatures for other temperature-sensitive devices; less heat inside the case is a good thing.
The traditional port cluster at the back of the motherboard is gone, in favour of vertically oriented ports fore and aft of the board. Bulky video ports are also gone—that means DVI, and possibly Displayport as well. Hopefully the focus will be on HDMI/miniHDMI and mini-Displayport.
The position of the CPU socket has been standardised and fixed. This means it is easier for OEMs to know where it will be, which means it is now easier for OEMs to design small cases that also act as heatsinks for the CPU. It’s hard to build a cooler into the case if you don’t know where the CPU is going to be; you’ll need to have flexible heatpipe arrangements to account for variations in its position. But no longer!
While there are currently no 5×5 boards available for sale yet, I look forward to a near-future of 5×5 boards catering to tiny-ish yet performant PCs. Especially the passively cooled ones. This also makes things easier for building custom options, such as this mini-ITX case-cum-heatsink. I look forward to building one like that within a 15×5cm footprint.
Hopefully I will be writing a follow-up post in a year or two detailing my next desktop upgrade on a 5×5.