RTX 5090 & RTX 5070 Ti not well thought out

Hi All,

TL;DR: I got excited building a PC and kept upgrading / swapping and building and ended up with a work station that is more than I can use. It was fun and frustrating, but I probably won't do it again. If you have advice or a suggestion on how you would use a 5090 and 5070ti in the same PC I would like to hear it!

So, this all started when the 5090 was announced. I signed up to be in the lottery to buy it at msrp from NVIDIA. I had an Alienware R15 with an i7 and 4080 with a 1300 w psu. The 4080 was fine but I had really wanted a 4090 for better fps in gaming and I was starting to explore local imagine generation. I got selected, bought the 5090 and went to swap it into my PC when I realized that I was not able to use the power connector that was in my Alienware PC.

I then decided I would sell the Alienware and build my first PC. At the time I was still building a gaming focused PC with a Ryzen 9 9950x3d the 5090 and 32 gb of ram (I tried to save money on the ram thinking I could upgrade later boy did I get that wrong). Then I had less time for gaming as I started to learn about Ollama, and then Llama.cpp.

I was constantly downloading and trying new models. At one point I had nearly 1 TB of models that would fit on my 5090 (gemma 4 12b, 26b-a4b, 31b; gpt oss 20b; nemotron 3 nano 30b a3b; so many Qwen models etc). Then it seemed like the better models kept getting larger, so I looked into getting a second GPU (ram prices were/are nuts and vram seemed like the better "investment"). I realized that I would not be able to run another gpu at its full PCIe lanes with my gaming PC as the Ryzen 9 couldn't support it. So, I started looking for used Threadripper hardware.

I found a 7960x with 96 GB of ECC DDR5 ram, a 5070 ti and 20 tb of storage for less than I built my gaming PC. I wasn't able to find much in regard to PC builds with a 5090 and 5070ti. Most builds were dual 3090s or other matching cards. Still after looking into it, I figured the extra vram and the fact that they were both blackwell GPUs would work out well.

I thought I would be able to just drop my 5090 into the threadripper workstation and I would be good to go. Unfortunately, the 5070 ti that came with it was a four slot card and the spacing just would not work with the motherboard (Gigabyte Areo D) layout and the cases that I had. So I put the 5070ti into my gaming PC, sold it, and bought a 2 slot 5070ti and put it into my workstation.

What does this have to do with LocalLLaMA? Well, while I was doing all of this the LLM space kept moving forward. I now have Hermes Agent set up running Llama.cpp and Qwen 27b Q4 on my 5090. I swapped to a Q8 to run across both my 5090 and 5070ti but the speed trade off was not worth the accuracy increase. So, I went back to running the Qwen 3.8 27b Q4 and my 5070ti is completely idle. Going from 32gb to 48gb did not have the impact I thought it would, at least not with my pairing. The 5090 is pretty quick when everything is loaded onto that card, and Qwen 3.8 has been pretty great on it too, that I have not found a good use case for deploying the 5070ti.

Hermes / Qwen suggested I run another Llama session with a smaller model on the 5070ti but I don't currently have a need to run something else. What would you do or suggest I explore?

Additional background context: I do not work in tech or software at all. I am an asset manager for a independent power producer, but I can not use my personal PC for work due to IT policy (I would have my agent working around the clock to review contracts, analyze system performance, track deliverables / open items etc). I have taught myself everything about PCs and local LLMs from creeping this and other subreddits / youtube videos. I literally have no one in my social circles that I can converse with about tech whether its PC building or hosting LLMs.