This is really a "How long is a piece of string?" type question. The answer depends, as others have said, on what you're trying to achieve. Fortunately, we're increasingly well-catered for when it comes to small form factors, so everyone should hopefully be able to find something that suits their purposes, requirements and aesthetic preferences.
Even for those arguing "it must be small because otherwise mATX" they are missing the point of bigger ITX cases. ITX is 17x17cm, mATX is 24x24cm ! Those 7cm on both sides can be used for different hardware, as you can see it in case of Prodigy - in ITX you can easily fit the whole watercooling loop in it, without really obstructing much; in mATX variant you will block few mATX slots with the radiator on top, and you will lose many hard drive positions. So while outside size is same, it is not same from features standpoint. Same applies for mATX vs ATX logic - for example PC-A05 ATX case is smaller than most of the mATX cases, only because you sacrifice many of the features. On other side a Cooltek U3 mATX case is 20.8 liters, so it would even fit in the 2nd ITX category from voting.
Big news here: Silverstone are about to release a 550W 80 Plus Gold SFX PSU. I'd heard rumblings of this for a while, and was expecting one at CES14 (Ryan Shrout talks about it in his video review of the new Silverstone Raven MITX 'Steam Machine' case). More info has just popped up here (along with loads more interesting news) "Question for SilverStone: What's up with the 550W 80 Plus Gold PSU? Answer: I can't give specifics on this due to embargoes. I can say that there will be a very impressive PSU in the SFX form factor very soon from SilverStone. It's damn impressive." If there is an embargo date set for journos, I can only assume it must be pretty soon.
SFX-PSUs still have the biggest problem with their tiny 80x15mm fans as these are very noisy. And the currently available 450 Watts is very sufficient for a decent mITX gaming-rig (100W CPU + 200W GPU + 100W for the board and the rest) even leaving a little overhead.
P8H67-I - 6 SATA ports: https://www.asus.com/Motherboards/P8H67I/ but you're right my current server/HTPC uses a mATX board from a retired old build. Although my wife has one of these boards in her Q11. I double up my server as HTPC as it's on all the time anyway. Also, nothing stopping buying an ITX board with low-profile SATA RAID card either. I think there's a market opportunity. And ooh that case is a custom design. I wish I had that kind of access to those materials and workshoppery Regarding SFX: No one wants to make one because they're not mass market. Same reason why there's way more ATX boards than mATX, for example, even though MOST people would suffice with the latter. People are generally not prepared to pay the premium for the smaller size and the higher power you go the more the premium becomes. You could probably do a half-height, high power ATX PSU with slimline fan, but again it's a hell of an investment for a niche market.
The Prodigy sits perfectly on my desk and looks great, that's really all there is to it. A smaller mini-ITX case wouldn't benefit me overly, space wise, so unless it looked even better there would be little incentive to downsize, considering the practical drawbacks. Sure, I could have gone for a micro-ATX case, but at the time there weren't any that I thought looked as nice, and mini-ITX cost about the same with no performance disadvantage. The CM 110 looks like a dull black box to me, no matter how well it performs or how cheap it is. The Silverstone FT03 mini is really the only thing that will draw me away from Bitfenix at this point, and I don't have that kind of money
Isn't it a case of 'if you build it they will come' though? At the moment the best SFX PSU you buy is a 450W model. I know in reality most people don't need anywhere close to that amount, but there is a certain mentality that 500W is a bare minimum. I have a feeling that Silverstones new 550W model is going to be the catalyst to kick off case designers to build small form factor PCs based on SFX, especially with the Steam Machine movement in full swing. You don't have £73.98?
Nope. These are small companies that build products according to risk-reward. No one is now actively pushing new standards in the PC industry unfortunately, it is an organic flow led by social noise and retail demand. And dayyymn if I was back in the UK I'd get rid of my Q11 and buy an FT03 mini. I've always wanted one, but selling on kit here is a PITA.
I actually don't But my point is more that I'd have to buy a new PSU and a slot loading optical drive in order to use that case properly. Damn you for making me actually consider it though, you bad, bad person.
It's a pretty little case, I built my mother's PC into the µATX version and modded the fans to run incredibly slowly, which coupled with a passively cooled HD5450 and Pentium G2120 has created an incredibly quiet, sleek machine. It's full of dust of course, but then parents' PCs always seem to be don't they?
Definitely 10-20 liters max. This size is enough to put full size PSU and graphics card of your choice. These two components define case size, I would say. Rest would be number of HDDs in the cage. This size should also let to install small watercooling loop, but would be perfectly sized for air cooled system. Compared to modded cases/scratch builds, for example my Nano Tower was 16L case with full size PSU 39cm space for graphic card and with two watercooling loops. It was enough for any hardware on market - apparently Silverstone liked it so much they made FT03 with same idea and component configuration In 2 months I'm about to start new project - smallest ever air cooled ITX scratch build, which will be big enough for full length graphic card and closed-loop watercooler for CPU and it will be around 9L (!), but it is a bit extreme I would say. Also I may look at getting patent for it, or we will see another new ITX case from Silverstone for Christmas
Cei and jrs77 has nailed it. I don't think the case has to be too big to even fit ITX board, CPU, GPU,PSU, HDD, SSD and Slimline DVD. Plus a watercooler for CPU. A SFX PSU will be enable in making the size even smaller. +1 on patent
My father has a pretty industrial-sized compressor and air-receiver so there's nothing electronic with any dust in it at home. Also nothing with any surface-mount caps/resistors left on it either I can point you in the direction of a patent attorney if you like
I'm in the 'does it really matter?' camp... small cases are always going to be a compromise... and most people aren't going to agree on what needs to go in order to get/keep the size down... You need to pick an audience and compromise accordingly If you remove the ability to accommodate full ATX PSUs/Big GPUs, you limit it's high-end gamin potential... Conversely if you do accommodate high-end kit you're limiting how small you can feasibly make the case without cooking the internals... If you remove the HDD bays, it won't be much good as a NAS/server Then do you accommodate an optical drive, do you make provisions for cable routing... etc. etc. In short, not everyone has a degree in tardis engineering and you're never going to please everyone...
I would either want: Silent, passive case for the Haswell NUC. for work. Or gaming: SFF Case with high wattage low noise PSU build in that can take a full length GPU as the short versions a still quite rare. How many short 670s where there? and where they not one of if not the only higher end GPU that had a short version that was mass produced?
