Smallest possible 2x 4090 machine?

[crazygurl69]

Budget (including currency): $10k+ USD.

Country: USA

Games, programs or workloads that it will be used for: 3D rendering

Other details (existing parts lists, whether any peripherals are needed, what you're upgrading from, when you're going to buy, what resolution and refresh rate you want to play at, etc):

• Parts:
  • 2x RTX 4090, ideally at PCIe Gen4x16 connections (each), minimum PCIe Gen4x8 connections
  • 64+ GB RAM
  • CPU unimportant, any reasonable 8+ core CPU with enough PCIe lanes should be fine
  • Storage unimportant, any reasonable 1 TB+ NVME M.2 SSD is fine
• Size / Case: Looking for as small as possible -- something I can carry through an airport in a backpack. I'd be open to a "laptop" as well (something like this old thing with 2x 1080s), but I haven't seen anything recent with 4090s (or even 3090s).
• Timeline: Immediately, ready to buy now if I can find something sufficiently small.
• Application: Real-time multi-GPU 3D rendering, involving lots of GPU to GPU communication (hence the 4x16 communication preference)
• Noise: Quiet preferred obviously, but noise is not a huge factor. I'm happy to use blower GPUs if needed (instead of the typical axial GPUs), or go to a full watercooling setup if that results in a smaller system. Size is the priority.

Thanks in advance! I appreciate the help here. I've looked around a bit and I haven't been able to find a modern laptop that comes close to the specs that I need, so I think I'll need a SFF PC of some sort. Even if I did find one, I think screens are easier to find when I travel compared to a 2x 4090 machine, so the space / weight is probably better spent on the increased GPU horsepower that would come from a real desktop GPU instead of a trimmed down mobile variant.

[itsabearcannon]

Quote

as small as possible

 

2x RTX 4090

Pick one. 4090's are all going to be triple-slot minimum minus some of the oddball Dell OEM 2.5-slot cards that come preinstalled in Alienware machines, so you're looking at a case with six PCIe slots minimum, 7 if you want the cards to have any airflow. That's pretty much ATX size and above, I'm afraid.

You could go watercooling if you wanted to cut that down to dual- or maybe single-slot 4090s, but a custom loop is unlikely to survive multiple trips on a plane with how much they change in air pressure, the bumps and turbulence, and the storage requirements.

 

If you need 48GB of total VRAM, look at your budget. The two 4090s are going to run you $4K or around that - you could get a 48GB A6000 for around $4000-$5000 that fits perfectly in most any ITX build with a straight dual-slot blower cooler.

 

If you need the combined ~33K CUDA cores.....you're SOL with the requirements you've given and you'd probably save more money just renting the compute online - I can find places offering dual 4090 rendering nodes online for $15/node/hour.

[crazygurl69]

6 minutes ago, itsabearcannon said:

Pick one. 4090's are all going to be triple-slot minimum, so you're looking at a case with six PCIe slots minimum, 7 if you want the cards to have any airflow. That's pretty much ATX size and above, I'm afraid.

You could go watercooling if you wanted to cut that down to dual- or maybe single-slot 4090s, but a custom loop is unlikely to survive multiple trips on a plane with how much they change in air pressure, the bumps and turbulence, and the storage requirements.

 

If you need 48GB of total VRAM, look at your budget. The two 4090s are going to run you $4K or around that - you could get a 48GB A6000 for around $4000-$5000 that fits perfectly in most any ITX build with a straight dual-slot blower cooler.

 

If you need the combined ~33K CUDA cores.....you're SOL.

Thanks for the reply. I do need the combined CUDA cores more than the VRAM, but going for the RTX 6000 Ada (with the blower cooler) is an interesting idea. The extra cost for that isn't an issue. That'd still require a SFF PC with 4x PCIe slots though, and I'm not sure how small you can get with that, since that starts to get into uATX territory for cases AFAIK.

[itsabearcannon]

Check this place out - they offer a 2x 4090 render machine online for $15/node/hour or 6x 4090s for $42/hr:

 

https://irendering.net/price/

 

Just for the cost of the GPUs alone that you're talking about, you could get ~265 hours of dual-GPU rendering time, or 95 hours of 6-GPU rendering time.

 

The form factor requirements you have are impossible, short of having a machine custom-engineered to your exact specifications by a shop that specializes in one-offs.

[crazygurl69]

1 minute ago, itsabearcannon said:

Check this place out - they offer a 2x 4090 render machine online for $15/node/hour or 6x 4090s for $42/hr:

 

https://irendering.net/price/

 

Just for the cost of the GPUs alone that you're talking about, you could get ~265 hours of dual-GPU rendering time, or 95 hours of 6-GPU rendering time.

Neat! I need the local rendering though, as it'd be for real-time 3D rendering to VR, where low latency is super important. I'll keep this in mind for other projects, though!

[Zando_]

5 minutes ago, crazygurl69 said:

Thanks for the reply. I do need the combined CUDA cores more than the VRAM, but going for the RTX 6000 Ada (with the blower cooler) is an interesting idea. The extra cost for that isn't an issue. That'd still require a SFF PC with 4x PCIe slots though, and I'm not sure how small you can get with that, since that starts to get into uATX territory for cases AFAIK.

Sliger Cerberus X. Closer to mATX size, but it fits EATX boards and multiple GPUs. Here's an example of one with two 3090s in it:

 

If you want dual x16 GPU slots you'll need HEDT anyways, which usually comes in ATX boards at the smallest (given the massive socket sizes of modern platforms). 

[itsabearcannon]

You might be able to talk to a custom PC builder that does their own cases, and see if they can make you something like a sandwich-style motherboard with an ITX base, mounting two blower A6000 GPUs vertically against one side panel to get fresh air with cowled exhaust to the back, and using a bifurcated PCIe riser to both cards to get you the size you're looking for.

But we're not going to be able to help you here. Your needs are specialized enough that you may need to go custom.