17L full ATX case -- worth pursuing?

[chx]

While mATX and Mini ITX really came far, the X systems with quad channel really require ATX motherboards. However, these have 7 slots which are really rarely used these days. If you are running Tri or Quad SLI this thread is not for you.The ATX factor requirement comes from the 8 memory slots eating up the space around the socket and the (rather large) chipset needs to be in front of the slots.

Here's my thinking. Take the Silverstone LC13B as an example:

Imagine cutting off the ATX PSU on the side. Use an SFX PSU and put it on top of the rightmost three slots. You still have 4 slots left. The chassis would be practically the same footprint as the motherboard itself and taking a guess from the Silverstone case for the height, that's 170mm. Height wise the photo shows a little clearance above the 100mm PCI height, the PSU should fit. The ATX motherboard itself is 244mm long, even SFX-L is only 130mm, the remaining space on the side could be used for disks.

Airflow wise, there are two 80mm fans in the back and likely the front could see two 80mm fans too, many memory modules are less 40mm (for eg Ballistix Tactical).

Video card wise at least some GTX 970 would fit.

Is this worth pursuing?

 

[SaperPL]

I think that this idea might be a little overkill since there were cases with SFX power supply attached where fans are in this photo. With such case you'd still get to fit standard coolers up to 60mm.

The idea of putting psu over slots is nice though if you'd want to use riser and flatten this case by putting the gpu over the motherboard but then you'd have to figure out your thermals.

 

[chx]

SaperPL, do you have an example of such a case ?

 

[SaperPL]

If you're talking about the psu over the motherboard - I know that those cases were quite popular back in PIII days but can't find the current ones:

I actually had few of such cases.

For reference you can check out current mITX cases and see how much space you need for psu over motherboard etc:

Extend the design to fit bigger board and you're ready to go.

Rather than putting power supply over the motherboard expansion slots I'd go for some attachment system for drives and 240mm radiator over there.

 

[bhtooefr]

One idea I've had for a tiny ATX case is using P3-era SFX PSU-over-motherboard layouts, with a dual 120 mm, maybe dual 140 mm (it'd be damn tight, though) radiator in the front case for CPU cooling.

The cases I'm most familiar with from that era were the HP case that SaperPL referred to (my family had a Pavilion 6535 - what an awful machine), and the Dell Dimension L-Series/2100/2200 case (I used to handle IT for a school with a fleet of L866cxes and 2100s, and I saved a 2100 from the dumpster and used it as my server for a few years).

So, of those two layouts, the narrowest is the Dell, at 168 mm (although it was not at all height-efficient, at 390 mm tall, given that it was Micro-ATX - the toolless mechanisms they used took a lot of space, and they pushed the optical drive up over the motherboard) and 22.3 liters. The HP case (based on the 6831, a Latin American-only model, which means they haven't scrubbed the specs from their site unlike the US/Canadian models) is 187 mm wide, but the reduced depth and height (330 mm for both) means that it's 20.4 liters. Both layouts are rather inefficient, though (the HP isn't helped by having a ton of cosmetic plastic on the top and front).

Let's go with both 160 and 170 mm wide for this experiment. 160 would make watercooling mandatory for all but the lowest TDP CPUs I think (a T-series CPU, for instance, would stay cool no problem on air, as 35 W TDPs are what SFX-over-motherboard layouts were designed for), 170 is a bit better.

ATX is 305 mm tall, add 10 mm for feet, add 10 mm for various chassis limits, for 325 mm tall.

Maximum PCIe card length is 312 mm, add 10 mm to the rear for the card bracket, add 25 mm for fans, add 40 mm for radiator, add 10 mm for various chassis limits, for 395 mm deep. (This is assuming a mesh front to minimize length.)

2.5" drives are a maximum of 70.1 mm wide, there's 68 mm between the fans and the motherboard, but the drives can overlap the motherboard a bit safely, even with the obsolete 101.85 mm length spec, so I'm not worried about that. And, they can be positioned so as to not restrict airflow from the radiator. I'm not providing for 3.5" drives, because this is a minimum config.

This would give a displacement of 20.6 liters (19.4 liters if the feet and rear PCI protrusion are ignored or left off - making it true SFF) at 160 mm wide, 21.8 liters (20.6 liters with the feet and PCI protrusion left off) at 170 mm wide.

So, let's restrict GPU length, because that only barely worked, only by removing the feet and PCI protrusion and staying at 160 mm width - a wider (easier to work in, more clearance for watercooling hoses) layout wouldn't work, an 8-slot (for quad SLI, if you're completely insane - and, SFX-L is a possibility, so powering it could potentially happen in the future, although not today) setup wouldn't work. Nvidia's reference cards are 10.5" long, so we'll go with that as a limit. Now it's 267 + 10 + 25 + 40 + 10 = 352 mm. And, with a 120 mm radiator, there's space above the radiator for two or three 2.5" drives - 40 + 25 + (267 - 244) > 70.1 - although this restricts the front panel (there's still enough for a power button at least).

At 160 mm wide, we're now to 18.3 liters all-inclusive, 17.2 liters minus feet and PCI protrusion. At 170 mm wide, we're now to 19.4 liters all-inclusive, 18.3 liters minus feet and PCI protrusions. Adding an 8th slot for quad SLI (0.8", 20 mm taller) means 19.4/18.3 liters at 160 mm wide, 20.6/19.5 liters at 170 mm wide.

Also, for more... sane layouts, a front-mounted vertical ATX PSU could be used, there's 88 mm of depth available with the removal of the fans and radiator, ATX is 86 mm tall in the normal orientation. I think you're restricted to 140 mm long non-modular PSUs (as in the NCASE M1) with that layout, though, unless you run short GPUs, or move them down. And, drives would have to be relocated (on a 170 mm layout, the side of the PSU is an option, and on all layouts, with restricting airflow towards the front of the GPUs, a drive or two could go vertically under the PSU (that wouldn't work in a Micro-ATX version, though, not enough height with SATA connectors even in a 5-slot chassis - maybe slide a drive or two above/below the CPU heatsink (assuming an aircooled build)?)), and the power button may need to be elsewhere. And, in a front PSU aircooled layout, a flipped fan may make sense to make the PSU provide intake air for the CPU.

 

[chx]

Oh you misunderstood my question -- of course I am well aware of the traditional ATX design and my humble old gaming desktop is in a Sugo SG05. The question rather was, do you have an example where an SFX PSU is on top of an ATX board?

 

[SaperPL]

I can't show you any currently being sold case with such config, I don't know of any. But I've shown you the old ones.

I actually think your idea might be nice to put the psu over the slots. Check out coolermaster elite 100 - they did that with mATX board and flexATX psu. The only problem is that you need to manage the onboard connectors down there like usb front panel and power switch etc.

 

[PlayfulPhoenix]

I don't think a ~17L ATX case is something that's going to be worth the compromises to all but a select few enthusiasts that have a very, very specific configuration in mind. And even then, I don't know if it would make sense even for those people, since it wouldn't be a layout that would adapt to the state of the industry a few years down the line.

We've (Aiboh and I, though mostly Aiboh) played with an ATX design in the past that's closer to 20L - we have preliminary designs for other cases and products, though Project Nova is our focus at the moment. But even that has significant compromises that we're unconvinced many enthusiasts are up for at this time.

What makes it challenging is the power supply. You have to support full ATX units (and even most super-long ones), and putting it below the PCI slots forces you to create lots of extra volume that's inefficiently used. The only real solution today is to move it to the front of the case, or above the motherboard. But then, you introduce a lot of thermal constraints and concerns that become very hard to address, especially with 3-4 GPU and/or overclocked hardware.

 

[SaperPL]

If you want to do this for the ram, you don't want the multi gpu then maybe you should go for something like this:




Notes:
- the case volume would be around 9.5 liters (330x320x90)
- that's mATX but full ATX will also fit there
- with gpu that doesn't have backplate there should be 7mm of clearance under fans
- there's 3 pcb riser pieces if you have pci-e x16 in the first slot or 2 pcb riser pieces if you have it in the second slot. You could also go for the 8cm long flexible riser
- there's literally one or two TFX power supplies that might be usable for such a config.
- hard drive placement might need to change depending on how much space the power supply cables will need.
- max supported cards would be around 26cm because the TFX modular plugs are there.
- you'd need to figure out if there's need to pump air directly under the gpu

That's a neat idea, I think, but it's not something that would work for manufacturing since there's problems with power supplies here and depending on one model is not a good idea.

 

[chx]

Heh, a very similar case, the GT3 was already built long ago and I owned it and posted about it here in http://hardforum.com/showpost.php?p=1041709249&postcount=20 and a gallery at http://hothardware.com/gallery/Article/938?image=big_comparison3.jpg&tag=&p=1

I wanted to avoid risers, you know.

And now I wish I still had my GT3 but I sold it when I moved to Canada. Pity

 

[SaperPL]

Yeah, then maybe stay with no riser option if possible. Actually your initial idea might be fine but I'd rather go with psu over motherboard + AIO cpu cooler rather than no sli for ATX.

 

[chx]

My idea would keep SLI: 4 slots would remain so 2x2 slot for videocards.

 

[SaperPL]

So what are you waiting for then? Grab some cad software, get parts from grabcad and figure out how to make your case.

 

[SaperPL]

Actually making 17L ATX case with ATX psu over the cpu is quite possible even with water cooling. I did the draft assembly and it looks so obvious to do. Why noone is making this?

Spoiler: concept

Case dimensions would be 330 x 305 x 168 mm

Coolers/blocks up to 55m tall. 280 rad mount in front of the case that would fit with fans when gpu's have water blocks.

 

[Urelure]

Actually making 17L ATX case with ATX psu over the cpu is quite possible even with water cooling. I did the draft assembly and it looks so obvious to do. Why noone is making this?

Spoiler: concept

Case dimensions would be 330 x 305 x 168 mm

Coolers/blocks up to 55m tall. 280 rad mount in front of the case that would fit with fans when gpu's have water blocks.

Not that I'm in need of an ATX system, but man, that is cool.

 

[iFreilicht]

Very neat. I'd like to see a build with that. Should work very well thermally as well.

 

[chx]

If someone builds that please make an option to use SFX/SFX-L PSUs for a few additional mm of CPU cooler

 

[bhtooefr]

Interestingly, it's worth noting that the ATX 1.1 spec allowed as little as 2.20" (55.9 mm) of clearance above the board (so, with the 8.1 mm LGA115x socket stackup height, 47.8 mm of cooler), in one configuration (external fan on the power supply, in the early days of ATX power supplies). However, it required there to be 2.75" (69.9 mm) of clearance (or 61.8 mm of cooler with LGA115x stackup height) without the external fan, to allow for Slot 1 (tall CPUs) with a power supply swap. I think the 2.20" spec was allowed with ATX 1.1, based on them talking about flexibility for chassis designers.

ATX 2.x and microATX allowed 2.80" (71.1 mm) of motherboard height and required 3.0" (76 mm) of clearance, the 4.9 mm gap being to give space for components to move in shipping without colliding.

Now, how tight can this go, and still stay in specs (violating the letter of ATX 1.1, but fitting within a compatible configuration)... you're at 168 mm wide, so subtract 86 mm of PSU, 55 mm of heatsink, and 8.1 mm of socket, and you're at 149.1 mm. 18.9 mm to add to things.

The minimum for ATX 1.1 "compliance" with an ATX PSU... 18.9 plus 55.9 plus 86 equals 160.8 mm wide. This has 47.8 mm of heatsink clearance.

And, this is ATX 2.x compliant with an SFX PSU - 160.8 - 18.9 - 63.5 (SFX PSU width) = 78.4, so there's 2.4 mm to spare, even.

At 330 * 303 * 161 mm, it's 16.1 l. You could even add 20 mm to the height, for 350 * 303 * 161 = 17.1 l but capable of quad SLI.