Hello all, just finished a build in the N-ATX v2 and thought you guys might enjoy my odd configuration.
Link to the picture of the finished build.
Long story short, I always preferred small form factor builds and recently got into LLM and AI. Most cost effective LLM builds usually involve multiple graphic cards (3090s typically), with server motherboards or multiple risers, built into server chassis, large cases or open frames. Didn't have any previous ATX builds or cases to take advantage of, so I would be forced to start from scratch - new case, new cpu/ram/board, multiple large gpus, new power supply, etc. Even limiting myself to second hand gear, it would be costly in money and time spent to research the compatibility of the various components and making them work.
Luckily for me, I was reminded that my Asrock Z390 mITX board supports bifurcation - thus I could reuse a number of parts I had on hand - cpu, ram, board, PSU, etc.
Was initially considering the Cerberus or Cerberus X - still rather large at 20-23L, relatively expensive for me (shipping and tax), and would still have a lot of "wasted" space. Most other cases have a similar issue for me - the first slot would be occupied by the riser cable, and I need at least an additional 4 slots (for two 2-slot gpus). A sandwich style case was a possible alternative, as I had to get a gpu riser anyways, but most max out at 3-slots spacing. Water blocks could used to slim down the gpus, but that would eat into the budget. I would rather spend more on better gpus.
Then I found the N-ATX - a 15L case that had compatibility with 4 slot gpus (in mITX configuration). the layout is ideal - 79mm for a "large" cpu cooler, fully exposed 4-slot spacing for the gpu, and minimal modding needed to make it work for me. Bonus points for ATX psu compatibility (in case I need more power), and relatively generous dimensions for the gpu (increasing the range of cards I could choose from).
And it is off to the races - I ended up with the following components
- Intel i9-9900K
- Thermalright AXP120-X67 Cooler with Noctua NF-A12x25 PWM
- Asrock Z390 Phantom Gaming-ITX/ac
- Crucial Ballistix 16GBx2 DDR4 3600
- SK hynix Gold P31 2TB x2
- Nvidia A6000 48gb x2 [Ampere cards, not Lovelace]
- Corsair SF750
And additional components to make it work:
- Silverstone CP14-R [19-pin header to Type-C Key A adapter]
- C-Payne PCIe Bifurcation Card - x8x8 - 2W
- ADT-Link K33JK-SI 250mm [double reverse]
- Cablemod PSU cables - gpu power cable for the bifurcation card, short cpu power cables for the gpus. rest of psu cable are stock
- USB 2.0 9pin to dual female ports
- Headphone/Microphone combo jack (from an Ncase M1)
I was not able to use the original gpu mount. To support the GPUs on the bifurcation card, I used several nylon 10mm motherboard stand offs - attached them to the bifurcation card, and wedged between the frame and the lower support. At rest, the weight of the GPUs are supported, just have to be careful when moving the case.
The pc is stable and runs like a dream, although I have not yet tried to stress test the system - I'm not sure how the SF750 would handle the theoretical 764W power draw.
As for the case, internally it is still very spacious. I have plenty of space for a beefier ATX power supply, but for now it is fine.
It looks like I could cut out a portion from the middle and reduce the vertical height and volume by a decent amount. (beyond my tools and skills)
On the other hand, if I had another 10mm or so of vertical height, I could try fitting a MATX board inside (for the 4 ram slots), but currently any of the connectors at the bottom of a MATX board with be blocked by the gpus.
Overall Im satisified with the N-ATX, the flat-packed package arrived safely, the instructions were clear and assembly straight forward. Thanks for a great case!
P.S.
On a tangent, when researching parts for the build, I tried to figure out how maximize the system memory - mITX boards are limited to two ram slots, so the most that consumer ITX can do is 64gb (ddr4) or 96gb (ddr5). There are higher capacity sticks, but those are server ecc memory, and there are no server itx boards. I could go MATX (4 ram slots), but that would affect case compatibilty. The closest was the Asrock X299 itx with 4 soddim slots, but the HDET cpu and board are hard to find and expensive given their age. A more modern option would be the deep-mITX boards from Asrock rack, which support the new cpus from Intel 12/13th gen and AMD 7000 series. They have iGPUs, which should allow me to minimize the load on the dGPU (for LLM tasks), However they cost significantly more than their consumer board counterpart, and there is no clear documentation if they support PCIe bifurcation. Size wise the deep-mITX should fit in the NATX without issues, even with an ATX PSU, so maybe in the future that could happen...
Edit. fixed the image links
