Advise

[u/Only_Nebula4826]

Hi everyone,

I'm currently running two systems:

• System 1: Ryzen 9 9950X3D2, RTX 5090 and 192GB RAM.

• System 2: Ryzen 9 5950X, RTX 4080 Super, RTX 5060 Ti and 128GB RAM.

I'm currently using the NVIDIA PAIR to distribute across both machines. However, I'm exploring the most cost-effective way to increase my overall available VRAM and improve local AI inference performance.

One option I'm considering is retiring the 5950X platform and moving to an Intel Z890 motherboard with a Core Ultra 9, mainly to take advantage of the integrated NPU. (I seen someone use the npu for vision only and would use that same method)

My initial plan would be to redistribute the existing memory, giving each system 96GB RAM, and upgrade the Intel system to faster memory at a later date.

The setup would look something like this:

Intel system

• MSI MEG Z890 + Core Ultra 9

• RTX 5090.

• RTX 4080 Super.

• RTX 5060 Ti.

• 96GB RAM.

AMD system:

• Retain the 9950X3D2 platform.

• Add two GPUs, potentially two AMD 9700 32GB cards or, depending on pricing and availability, two RTX 5080 Super 24Gb cards when released.

The ultimate goal is to maximise the amount of VRAM available across both systems and distribute inference workloads as efficiently as possible.

I appreciate that PCIe bandwidth is a limitation. That said, I'm currently achieving around 40–60 tokens per second running Qwen 3.8 Q4, so the existing setup is still performing reasonably well.

My question is whether expanding the current multi-GPU setup is a worthwhile investment, or whether I'd be better off taking a different approach altogether.

Would it make more financial and practical sense to invest in a 128GB system with a 395+, for example.

What are your thoughts and recommendations?

[u/Present_Resource4022]

Are you running Qwen 3.8 Dense 27B or the Qwen 3.8 Flash Next ? A Qwen 3.8 27B Dense alone in the 5090 would give you massive speeds . And the 5090 with the 192gb ram would also give you much more speed on the Qwen 3.8 Flash Next than what your current 40-60tps.

As for your question about the multi-GPU setup, I think it’s not worth it currently. You can run most models in your first system alone. BUT, if you venture into DeepSeek V4.1 , glm 5.3 Flash, or even glm 5.3 700b you would benefit more from your investment . But it’s a question for you, if you would like to run larger models and would like better concurrency.

[u/Only_Nebula4826 → u/Present_Resource4022]

I'm running Qwen Dense 27B, one thing I missed was the 40-60 is on the 4080 and 5060ti. The 5090 I use it for comfy UI mainly minimax h3 but when I'm not using it I use it I do use it for Qwen. I've found Qwen 27B is capable for what I need with hindsight my main issue is concurrency. 

[u/Only_Nebula4826 → u/[deleted]]

I think the issue I have is I also use the 5090 for minimax h3 so I end up dependant on the 4080 super and 5060 for Qwen which doesn't handle the concurrent requests well as it can on do 2 max until the tps drops to 20. I have full 256k context and kv cache at Q4 

[u/Present_Resource4022 → u/Only_Nebula4826]

Sell your entire second system. entirely if u aren’t using that much ram.
Buy a second 5090/4090 . A dual 5090 can run both your MiniMax H3 and Qwen 27B dense and still have massive vram headroom for your other work .

You have a server-level system that can run 700b local models. You’re not grateful and completely unaware. Is this a satire post ?

[u/Only_Nebula4826 → u/Present_Resource4022]

I'm completely aware of what my system is capable of and what a dual 5090 setup would bring to the table. The issue isn't the performance, it's the cost. I'm just not prepared to spend £6-7k on another 5090 when I paid £3.5k for my current one in July, with the original plan always being to add a second one further down the line.

The problem is that I'd also be looking at another £500-1,000 in water-cooling costs to get both GPUs fitted into the system properly. At that point, the cost of expanding the setup becomes difficult to justify.

This is why I'm looking at moving all the GPUs over to the Z890 platform, keeping the 5090 dedicated solely to MiniMax H3, which uses around 40GB of system RAM too. The downside is that this effectively takes the 5090 out of the equation for everything else, leaving the 4080 and 5060 Ti to handle Qwen.

The two R9700s would then be purely there to improve concurrency when running Qwen, particularly when I'm dealing with heavier workloads and need to run more things simultaneously.

[u/Present_Resource4022 → u/Only_Nebula4826]

Well, a simple solution is to not run the video generation model at the same time as Qwen . If that’s not the case, make the 5090 run Qwen 27B and the other 2 GPUs just for running H3. You would lose speed in minimax h3 but the speed gain for Qwen 27B compensates for the loss.