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Discussion Starter #1
Something I've been putting together for fun after looking at a few things such as Valve's steam machine prototype, NCASE's steam machine prototype, and a few other things. Here are some photos in SketchUp. The frame of the case is made out of three parts like the NCASE steam machine: a front panel assembly, rear panel assembly, and a bent midframe (see here for a clearer idea, courtesy of Necere). The case was made in mind with 1.5 mm aluminium (glass bead or sand blasted, bright dipped (?), and anodized). This is still a work-in-progress.


  • 2-chamber design (1. Motherboard and SFX PSU, 2. GPU and HDDs)
  • 315 mm GPU chamber (312 mm is the maximum length and specified by PCI-SIG PCIe specification)
    • Actual maximum length will be lowered because of power button assembly taking up some space in the GPU compartment. Rarely do many cards come close to this length (well, there's a few 390X aftermarkets that exceed this length but there are also some below this length). Later cards will be getting shorter and shorter with the introduction of HBM as seen in the new AMD Fury and Nano cards.
    • GPU will be connected using a riser card based on a ribbon cable. The PCB of the riser card will be mounted to the midframe.
    • A 10.5" GPU (Titan X/980 Ti/980 sized card) is shown for reference.
  • SFX and SFX-L support
  • CPU Cooler height restricted to the specified mITX component height restrictions (57 mm from PCB. Average height of Intel socket structures are approximately 8 mm, leaving you with 49 mm of cooler height. The best performing cooler you can fit in here is probably a Cryorig C7). There is 1-2 mm of extra clearance just in case. The 57 mm clearance height specification also means that ASUS boards that use a daughterboard perpendicular to the motherboard for the power regulation circuitry WILL fit in this case (those are designed to comply with the maximum component height restrictions). All dimensions were taken from formfactors.org.
  • Motherboard cutout (not finished but planned, part of the reason this case stays within spec)
  • Storage: 3 x 2.5" Hard Drives (15 mm height maximum), M.2 (need to check if clearance requirement changes for M.2 SSDs mounted on back)
  • Dimensions (with calculated side panels on. Dimensions of current WIP are slightly smaller due to some missing panels)
    • Height: 73 mm (not including case feet)
    • Width: 321 mm
    • Depth: 319.5 mm
    • Volume: 7.49 L (not including case feet)
      • I can try to make the case a bit shorter though to try to compensate if support for 300 mm graphics cards is deemed irrelevant, but I can only make it so short so that the SFX PSU touches the edge of the 24-pin side of the motherboard.
  • Valve Steam Machine Prototype Dimensions (for reference), all dimensions are approximates Valve gave:
    • Height: 73.66 mm
    • Width: 304.8 mm
    • Depth: 314.96 mm
    • Volume: 7.07 L

Things incomplete:

  • Left and right panel covers
  • Ventilation (need to choose a grill pattern(s) and layout)
  • Front Panel Cover (to attach in front of front panel assembly)
  • Power and USB (Front Panel Cover)
  • Screw and Panel Mount Holes
  • Power Supply 3-prong extension cable to back of the case
  • Motherboard cutout
  • Midframe cutouts for PSU power cables and SATA cables along with GPU riser card
  • PSU mounting bracket

This case is designed to take three 2.5" drives. The heights of the mockups from left to right are 9.5 mm, 12 mm, and 15 mm. All dimensions were taken from the official SFF-8201 document describing 2.5" hard drive dimensions, connector positioning, and mounting hole measurements. The GPU is approximately 5 mm from the midframe in this compartment from the restricted component height area from the back planar side of the GPU PCB. I searched up the thickest backplate I could find dimensions for (at least the one that looked thickest, and it was the Heatkiller GTX970 backplate which is about 3 mm thick so there is some space left, though barely).

Hard drives are mounted under the GPU. The original plan was to have them above the GPU behind the back of the GPU, but from some of NCASE's testing that seems to be a rather poor choice, so this is the only other viable option in my opinion. Here is the link to the post after testing.

Quote: Necere
So here's what's going on: I did some thermal testing over the weekend and I'm not entirely satisfied with the results. The CPU and PSU cooling aren't an issue, it's the GPU side and the drives that are a concern. I tested with a reference (blower) GTX 780, and while it ran at its rated clockspeed @<83C, the backside of the card and/or some components (VRMs) were obviously getting quite hot. I say obvious because while I had no way of measuring it, there was a notable smell of hot plastic, which I don't find acceptable. Now, this is a fairly hot running card (250W TDP), but it's nevertheless something the case ought to be sufficiently designed to handle. The bottom line is that you really do need some active airflow across the back of the card - relying completely on the card's fans is fine for the what the heatsink covers, but inadequate, IMO, for cooling the parts of the card it doesn't. Honestly, I should've listened to my own advice on this.

What's more, drives temps got pretty high. I had an 2TB 2.5" drive installed at the back and it saw 50C while the GPU was under load. So Saper, you were right about this, and in my theorycrafting I neglected to take into account just how well aluminum conducts heat. In fact, under GPU load conditions, the entire rear part of the case becomes completely heat saturated and basically turns into an oven for the drives. The situation might be better in a case like the RVZ02, which has the same drives-behind-the-GPU-separated-by-a-partition layout, due to the lower heat conductivity of steel and the plastic drive mounting. But clearly for an aluminum chassis, a different design is in order.
The case works with SFX and SFX-L power supplies. The exhaust end of the power supply sits 20 mm from the end of the midframe (21.5 mm from side of case) and will require a right angle 3-prong extender like seen on the NCASE M1. I don't know the dimensions of 90 degree 3-prong power connectors so I do not if this distance can be reduced to give more room on the other side of the PSU where the power cables come out (I hope so).

Now for the part about the motherboard cutout I mentioned earlier. mITX spec (which refers to mATX spec) states that for the secondary (bottom) side of a motherboard that you MUST have 0.250" or more clearance. The motherboard standoffs themselves are actually only 4.85 mm. However, due to the cutout and some extra spacing, the actual distance from the bottom of the motherboard to the closest surface (which is now the back panel due to the cutout) is 6.35 mm. What I am unsure of, however, is if this distance needs to be changed for the use of M.2 SSD's on the bottom of the motherboard (since most mITX boards have the M.2 connector on the bottom of the motherboard), so I need to find a source to check this. Motherboard minimum distance trick is courtesy of Necere.

Quote: Necere
Most of the case is 1.5mm. Currently the standoffs are 3.5mm, however the cutout on the motherboard tray encompasses everywhere there's likely to be extended features on the back of the motherboard (e.g., CPU cooler backplate). The cutout allows 6.5mm of clearance to the side panel.

The hard drives are mounted on a removable bracket just like on the NCASE M1 with it's fan/radiator/HDD mount assembly. I tried to remove as much aluminum as possible from the bracket to allow air to pass through to the GPU.

The cutout in the front panel assembly you've been seeing in some of the photos is to make it easier to insert or remove the SFX power supply since the area between the motherboard and power supply is likely to be crowded with cables. The cutout allows you to grip the top sides of the power supply to move it around to make it easy to move.


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I didn't read through 100% of your post but skimmed it really... but since you're using sketchup, make sure to take advantage of the 3D warehouse!
Alot of times you can find things like case fans, GPU's, CPU coolers, etc in the warehouse to add to your model. I'd utilize a few of those and see if that helps your design.

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Discussion Starter #3
Originally Posted by Cakewalk_S View Post

I didn't read through 100% of your post but skimmed it really... but since you're using sketchup, make sure to take advantage of the 3D warehouse!
Alot of times you can find things like case fans, GPU's, CPU coolers, etc in the warehouse to add to your model. I'd utilize a few of those and see if that helps your design.
Awhile ago I fiddled around with 3D warehouse and wasn't exactly all that happy with it. Much of the issue for me was graphics cards models all varying in the sizing of their connector sizes which was quite annoying to work with since I couldn't get exactly where the GPU was supposed to be positioned relative to the motherboard. I tried the best I could by skimming through the publicly available PCI-SIG documents for PCIe 3.0 spec that have been released though those contained fairly little electromechanical stuff so I salvaged what I could from the consistent models.

Rest of it is great though. Thanks for the suggestion. :)

Made some small progress by just making a PCIe ribbon cable and folds on the sides of the front and rear assemblies for the side panels to go onto.

I need to open up my computer and see how much space a bent (90 degree) 8-pin connector will take up since 1. I can't expect everybody to source out low-profile 8-pin connectors and 2. I can't find source for the 90 degree 8-pin cables used in Valve's steam machine prototype and the Alienware X51. Currently I have 2cm of room from the top edge of the GPU pcb to the side of the case for the 6 and 8-pin connectors to fit into. Once I get some measurements in my spare time I can probably reduce case volume by 0.1-0.3 liters or so by just reducing that distance.

I also need to find if there's any sort of minimum distance something can be from the edges of the motherboard. I currently have it space such that there's 5mm of space between the motherboard (PCIe connector side) and the midframe where it bends. If I can drop that distance, I will because the GPU prongs still haven't touched the 0.100" keepout zone around the motherboard rear I/O cutout yet so I can keep pushing it.

The last thing I want to do right now is drop GPU max length to 295mm if I don't have to. Goal right now is maybe 7.2-7.3L. I could save some more space by going with a design similar to the Dondan A4-SFX but the issue with having something right next to the back planar side of the GPU still stands. I saw some of his thermal tests and was a bit concerned with temperatures, so this is probably the most efficient design as far as heat goes.

Edit: tested using a 6-pin unsleeved cable and it measured 1.7 mm from where the pin sheaths on the connector start to the bend of the wire, so for sleeved cables it will probably be a bit more (might actually not work with sleeved cables). Looks like I will be keeping it at 2.0 mm for clearance from the top edge of the GPU PCB. I'll look into shortening the overall length of the case a little bit. I think the last adjustment I can try to make is moving the midframe closer to the bottom side of the mITX board (PCIe slot side). I looked through the mATX and mITX spec sheets (since mITX references the mATX one) and I couldn't find anything regarding clearance from the edge of a motherboard.

Edit: Still couldn't find anything, so I assumed the closest I can get from the edges of the PCB to the metal on the motherboard is the distance the motherboard is from the rear panel assembly (as specified by how far the I/O cutout is to be from the motherboard) which is 0.083" (2.1082 mm). So I save about 3 mm on width. Height I can't make any smaller without going out of spec or giving me some really ugly numbers (I had adjusted the case dimensions to whole numbers to make manufacturing much easier and made all other dimensions so that they weren't irrational or repeating endless numbers; same goes for width and depth). If I drop the total case length to 314 mm (so subtract 4.5mm for the 3x 1.5mm panels (front + rear assembly, front panel) and then 10 mm just in case for the power button assembly, that leaves 299.5 mm of GPU clearance, though more effectively 299 or 298mm so that the end of the GPU doesn't hit anything). The volume is now ~7.31 L (73 mm height x 314 mm depth x 319 mm width all divided by 1 million).

Edit: Nevermind on shortening the case. I just checked the lengths of aftermarket R9 390X, R9 Fury, and 980 Ti cards are really, really long. There are quite a few that go past the 312 mm length limit set by PCIe SIG. 300mm might be the most I can support though since there are generally some "reasonably" sized aftermarket cards if none of the stock ones are available. We'll see. I need to keep thinking this over.

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Discussion Starter #4
Was a bit busy so progress halted, but now I'm free to work on this again!

So I did some research on if it was necessary to increase the distance between the bottom surface of the motherboard and the side panel to account for M.2 SSDs and the answer appears to be a no. So here's the M.2 spec sheet by TE connectivity:


If you click on the quick reference guide PDF it'll download it, just a heads up.

Also used this: http://www.mouser.com/pdfdocs/M2ConnectorBrochure201412181.PDF

So the tallest connector is 4.2mm double sided connector which allows for PCBs with components on both sides of the M.2 card (this is known as the H4.2 connector officially). This connector supports a maximum component height of D5 on both sides, which is 1.50 mm of clearance on both sides of the PCB. So that means the distance from the bottom planar surface of the motherboard to the top of a M.2 SSD (D5 module thickness) mounted to the H4.2 connector is 2.54mm (distance from bottom of mobo to bottom surface of M.2 SSD) + 1.5875 (1/16 thick PCB) + 1.50 mm which is 5.6275. With the minimum distance of 6.35mm from the bottom surface of a motherboard to whatever surface is below that, you have 0.7225mm of clearance from the module to the side of the case. Now from what I can tell on page 9 of the Mouser PDF linked you need only 0.10 mm of clearance from the top of a module to the bottom planar surface of the motherboard (the diagram right under "Double Sided Module" that says 4.2/3.2/2.8 H to the left of it), so this is plenty.

Regarding the case, I've made a motherboard back cutout and I just realized that I had 7.85mm of clearance from the bottom of the motherboard to the side/bottom panel. That will change.

But first I need to see how close the SFX PSU is to the top panel. I'll try to keep motherboard standoffs as long as possible just in case certain backplates exceed 0.250" from the bottom of the motherboard.

Edit: 3.5mm clearance from PSU top to the top side panel. Looks like we're reducing it.

Edit: new dimensions with reduced height: 71.5mm x 321mm x 319.5mm (height x width x depth). Volume is 7.333L.

I can further reduce the height by 2mm max (probably won't do the full 2mm so the top of the SFX PSU doesn't hit the side panel) and I plan on reducing the width by 10mm because the plan is to bundle low profile 6 or 8-pin power connectors (if it goes to production). So if I reduce height another 0.5mm (top of PSU meets fold of front panel assembly) and reduce width 10mm, that gives me a volume of 7.055L (Actually smaller than the Steam Machine prototype).

Distance from the edge of a 2.5" drive to the vertical part of the midframe is right below 26mm which is concerning because from the connector bundled w/ my mobo (in sig) the connector portion sticking out of the drive is 15mm in length and I can't really get it to bend that well with the 10mm I have left. It would end up increasing the cost of the case more if I were to bundle a cable like Silverstone's 90 degree super low profile cable.

Edit: Might need to reorient the hard drives because I didn't take into account SATA power cables.

Edit: Dropped height 0.5mm: 71mm x 321mm x 319.5mm. Volume is 7.28L.

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Discussion Starter #5
I may as well post photos of the updates from the height drop.

So things I still need to complete are the placement of the 3-prong power connector, PSU mounting bracket, revised HDD mounting bracket, midframe cable routing cutouts (for HDD and GPU power/data cables) and the side and front panels. So once again the supposed dimensions of this current model are listed above.

There are some dilemmas I have with future decisions regarding this case. Originally this started simply as a pursuit of the smallest (yet within specification) case possible using the Steam Machine Prototype layout (arguably the most efficient layout) with no commercial prospect. There is still no commercial prospect (I don't have the resources necessary) but ideally products are designed to be used by a general public. So this brings us to a few things:

First is GPU power connector clearance. I searched for awhile but I can't find the source of the 90-degree 8-pin and 6-pin power connectors Valve used in their Steam Machine Prototype, and bundling those only serves to continue to increase the cost of the case (I don't find this very feasible unless I can bundle two 6+2 pin 90 degree connectors which don't seem to exist, so the only solution would be to include two 90 degree 8 pins and two or one 90 degree 6 pin). This limits how much I can shave off the overall width of the case just to reduce the volume to 7.05 liters. So I start sacrificing costs for the sake of going small for a difference that is basically negligible as far as use goes and adds inconvenience to both the user and manufacturer by adding extra costs for extra unnecessary cables. I highly doubt 1 cm difference in width in an already small case is going to be night and day for anybody.

Now I'll detail the changes to the HDD mounting mechanism. I want to do something like now Lian-Li has it where you screw in four screws with rubber o-rings that slide into circular cutouts on the bracket (if you want an example, look at how HDD's are mounted to either the front or bottom of the NCASE M1). This makes installation easy and tool-less, and also makes for a simpler case design because I don't need to create HDD caddies and I don't have to create vertical pieces of metal that can risk having these protrusions hit the GPU (worst case scenario it makes contact with GPU fans; Lian-Li has a perfect example of this mechanism here). Ideally I make the side wings that make contact with the case shorter while keeping the same height for the middle part of the assembly because it gives me more room on the flaps of the front and rear assemblies to put things like Lian-Li's push-button panel mounting mechanism.

Anyways, with this mechanism I start running into issues as to the maximum z-height I can support for hard drives. Currently there's about 3.9mm clearance between a perfectly straight GPU and a 15mm HDD (direct contact to current bracket). With this mechanism I probably cannot support 15mm drives. The reason I'm so keen to support 15mm drives is because, most likely, people will use Western Digital's 2TB 2.5" Green drive, which is 15mm tall, the largest 2.5" consumer drive you can get right now (both in size AND capacity). If I restrict height to 9.5mm the largest capacity you can go per drive is 1TB (still plenty) but I'm quite sure there will be people unhappy with the fact that they cannot fit 6TB into this case in 2.5" HDDs (file servers).

The alternative mechanism is to make sure the entire length of the bracket is in contact with the side panel and to use countersunk screws to mount the HDDs. Between the HDD and the bracket would be rubber pads to reduce vibrations and prevent direct contact from PCB to metal. This makes installation more difficult (no longer tool-less) but will definitely allow for 15mm tall drives.

I've also been considering people who might use this specifically for a file server. I'm considering brackets like what NCASE currently does that allows users to stack 2.5" drives (their double drive stacking bracket for 2.5" drives).

I can drop the height another 1.5mm (so dimensions are 69.5mm x 321mm x 319.5mm. Volume is 7.13L).

The issue with dropping height another 1.5mm is that the side panel now makes contact with the PSU. I don't exactly know if it will cause any issues as far as vibrations go so this is a questionable decision.

And the 1.5mm drop in height brings me to my last dilemma. I think some people need to gain an understanding of what every millimeter means to a case this small, and how negligible differences in your x, y, and z dimensions can lead to a sizeable volume difference (I'd call 0.15 L sizeable at this point because with cases this small, 7.28L vs 7.13L feels like a rather large difference, at least to me). So ultimately it's a balancing act between smallness and good user experience/convenience.

Anyways, hope everybody enjoys this small update.

Edit: One other thing. I may remove the bar between the two PCIe slot openings on the back of the case. It creates a cleaner aesthetic on the back and removes another piece of restriction for a positive pressure system (I'd call GPU fan close enough to the currently-planned intake area to call it an intake that creates positive pressure). Any thoughts on this? The fold where you screw in the expansion card will be widened to offer it more support if the middle bar support is removed.

Also, current front panel layout will be a blend between the Dondan A4-SFX and the Steam Machine Prototype. I want to use a large circular concave power button that's centered in height (other option is that it sits closer to the bottom horizontal edge) and a single USB type A or type C port at the bottom right of the case when laid horizontal.

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Discussion Starter #6
Switching over to a new design similar to that of the Steam Machine and SENTRY by SaperPL over at Hardforum regarding on how to separate the GPU + HDD chamber and the Motherboard+PSU chamber.

So if you look at the current layout, there's a 1.5mm gap between the midframe and the side panel since the flaps of the front and rear assemblies are folded over. That's a lot of wasted space above the GPU chamber and below the motherboard chamber. The current layout also requires the use of some really short standoffs. While the cutout provides the 0.250" clearance necessary for areas contained within it, the edges of the board only have maybe 3.5mm of clearance (need to check, but it's really short). The tallest feature from the bottom of the motherboard is limited to 0.200" (5.08 mm) and while usually things don't populate the edges of the motherboard, it's better safe than sorry. More clearance makes it less likely for shorts too so it's just general safety.

Minimum height was also restricted by this design since the PSU determines this. I can't reduce the height too much more with this layout since eventually I'll make side panel contact with the PSU which will cause vibration and noise issues. At that point I still have a wasteful 1.5mm area of empty space below the PSU caused by the foldovers from the front/rear panel assemblies.

The way the old layout needed the panels to attach was also incredibly awkward. Look at the RVZ02 and you'll see why. It doesn't work very well for methods such as Lian-Li's push-pin system or metal sliders/clips since one surface usually ends up freefloating, just resting on the frame instead of attached.

I did some experimentation a week ago that use a construction style like the two systems mentioned above (more like the Steam Machine Prototype): a single bent piece that serves as the base of the case along with the front and rear assemblies, then a separate divider between the two compartments that will be riveted or screwed in. So we've reduced the amount of pieces from 3 (front panel assembly, rear panel assembly, midframe) to two simpler pieces (a single base assembly and a divider). I think the volume turned out to be about the same size as the Steam Machine Prototype too so also a thumbs up.

We're still keeping the motherboard cutout unlike the Steam Machine prototype. The difference now is that the bottom side panel cover will now make full contact with the body (shouldn't be too big of a deal). Standoffs are also taller now so we have 4.85mm clearance for mobo components not encompassed by the motherboard cutout: I'll raise the standoffs to be as tall as possible if the case allows it so there will be no clearance issues anywhere for secondary side components.

I'm also switching over the side panel mounting mechanism to the slider one used by the Steam Machine Prototype. It's just much more convenient and requires only a taller fold at the sides of the case. I'm thinking about having both panels do this, so the folds might be a bit tall. I'll try to get some work done on this next weekend.

Edit: leaving some screws and parts here for future reference:


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Discussion Starter #7
More updates!

So I switched over the construction of the case as said in the last post. I dropped the number of 2.5" HDDs supported from 3 to 2 because in the former layout there was very little space for the SATA and SATA power connectors in the 3 HDD layout. This new one gives you more space to work with it (the area on the chamber divider between the SFX PSU and HDD area will have a cutout for routing cables, giving you more room for the SATA and SATA power cables for that HDD).

Case width was reduced another 3mm by moving the GPU closer to the motherboard side 3mm. I outlined earlier what I think is the minimum clearance I need from the edge of the motherboard PCB to some perpendicular planar surface (like the rear edge of the motherboard to the back side of the case). I put in some guides that outlined the 0.100" (2.54mm) clearance zone need around the motherboard rear I/O cutout and saw I could move the GPU 3mm over before hitting this zone (it was slightly more, but the decimals were quite ugly so I kept it at 3mm).

Anyways, time for some photos:

So I need to create a large cutout below the HDDs to allow air to go through the currently nonexistent cover panels that are on my to-do list. I need to make the side rails for the covers to stay on along with a front panel.

HDD clearance is looking good for now: this is the distance between the GPU (assuming no sag) and a 15mm tall 2.5" HDD (Samsung's Spinpoint M10P is 4TB which I just found out about, so you can fit 8TB of storage and then a M.2 SSD).

Current dimensions using this new layout with 1.5mm cover panels added on are 315 mm (w) x 69.5 mm (h) x 319.5 mm (d) which gives a volume of 6.995L.

Edit: Dropped another 1.5mm off height. Same dimensions as above except height is now 68mm. Volume is 6.84L. Looks like I might be able to increase the length of the case by a bit. I can actually add another 10 mm in length and still be at 7.07L to most likely allow space for 312mm cards (max by spec) and the power button assembly.

Edit: http://www.anandtech.com/show/10042/seagate-2-5-inch-2-tb-hdd-smr

Edit: found general PCB clearance spacings list. http://www.smpspowersupply.com/ipc2221pcbclearance.html
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