The Future of the Computing Platform

I'm in love with NUCs. Even though I usually despise the Intel marketing terminology (because they always trademark it, and because it usually sounds silly like ultrabook) in this case they nailed it on the head.

Firstly, the desktop. Or more specifically, I'd call this the class without an internal battery, because size is the topic. ATX and even micro ATX mainboards are now complete overkill. The only reason they even exist is exclusively graphics cards - and only the most insane users run multi-card configurations (note - the difficulty with multi card configurations is probably on the foundation of how hackneyed the entire platform is, but ranting about hardware architecture is something I have already done, and something I will probably do again in the future. Regardless, if you discount the graphics card slots, what can you really put in a pci slot anymore? Let's list them:

•  Discrete Audio Cards: Only for audiophiles. And if you care, just get a mainboard with beefier integrated audio. Asus even has a z87 board with a discete class audio solution embedded into the board proper. You don't need a coprocessor because pcm to onboard analog signaling is dirt cheap, and you often end up using digital audio out anyway in which case you can often just transport an aac or the pcm stream anyway. Note: spdif fuckers, get opus support in digital audio standards yesterday and junk all that other crap.
•  TV Tuner Cards: One, tv is dying, two, there are usb tuners. When I built my grandparents rig I got them an internal pci tuner under the assumption it gets better quality. In hind sight, probably not. On the first point, broadcast television is already going the way of the Dodo and I would never build a new system around converting dvb-t or a signals to mpeg2.
•  Raid Cards: The integrated raid controllers on most mid range motherboards are sufficient for 3 - 5 disk raid 5, and really, if you are even thinking of consumer raid this is where you are looking. Servers already have entirely different pcb form factors anyway, so you can keep dedicated pcie raid cards there just fine. Additionally, raid 0 with ssds has no performance improvement (maybe sata express will change that in a higher per channel bandwidth world) but I doubt it, because principally ssds already have radical random reads and writes. This means you might as well raid 1 with ssds rather than raid 5, and SSDs aren't like mechanical disks where one memory sector going bad kills the drive. You just don't need that redundancy class even in a homebrew home server. And again, if you do, the integrated raid is often good enough.
•  PCIE SSDs: These have a claim to fame in how sata 6gbps is at its limit and the only way to get more bandwidth in consumer hardware right now is pci express lanes. However, the interconnect isn't really targeting block devices, and the big 16x slots are overkill for 1GB/s sequential read ssds.
•  Network Switches: This is one that is harder to replace because a four way splitter has peak bandwidth requirements of 4gb/s. It isn't a block device so you can't stick it on sata 6gbps, even though that would make sense. Though, again, who is building a system with a network switch? I intend to, but I'm weird. Niche markets shouldn't dictate consumer standards.
•  Port Expansion: ie, more usb3 ports on a hub card. Like integrated audio, this should also be integrated to satisfatory levels. If you need more, you are a niche.

 Overall, there are just not many cases where 99% of people would want an expansion card *besides* for a gpu.  Likewise, this isn't 2005 anymore, and you aren't likely to upgrade your processor but keep the same motherboard. You pack a processor, mobo, and set of ram into a system, and leave it like that. You might get more ram (ie, a second set if you only bought one) but even that is rare, and you could have just bought double capacity from the start.

I predict a new world of form factors - for the classical enthusiast class, a small mitx size board taking up to 2 sodimm slots and a socket in the 20 - 30mm range rather than 35 - 50 (since large dies are overheating anyway), mpcie and msata completely replacing standard pcie slots, and 2.5" mechanical drives becoming standard under-the-board connected disks. The only exception is gpus, which won't be able to easily migrate from high bandwidth 16x lanes with space for heatsinks and dedicated fans running on 12v to pcie 1x at 3.3v with no fan options unless the device makes room. But APUs are now proving themselves very capable, and unified memory is a huge benefit for simpler implementation. And all 3 big players have apus (Nvidias are just ARM based).

 Even smaller than that, I expect soldered boards of combined pcb + cpu + memory to become common, since you rarely upgrade any of those parts, and becuse all 3 are always mandatory in any build. It enables smaller units when you don't need to worry about standard ports and sockets.

The enthusiast market won't go away, but likewise these big behemoth motherboards are also dinosaurs. There are connectors for these smaller form factors, and NUCs are paving the way, although the combination of case and pcb isn't great. What you really want is a case and a motherboard standard with a simpler power connection architecture (so you could have an external or internal power brick). But they are the future, and it will be small.