Be aware that you pay a significant performance penalty for going over occulink.
The hit modest for fully offloaded dense models (like Qwen 27B), but dramatic for hybrid inference of big MoEs.
Even my old 3090 got a noticeable performance gain going from a PCIe 3.0 x16 riser to a PCIe 4.0 one.










First of all, I mean zero offense with any purchase decision. A 5090 is very good.
…But if I were paying that kind of money, I’d probably get a 4090 and a new motherboard/CPU instead. Maybe a used DRR4 threadripper system.
Hybrid (CPU + GPU) inference is where it’s at these days. It opens up a whole world of huge MoE models, whereas on an 5090 you are stuck with Qwen 27B.
Having a fast CPU, with lots of RAM channels, with full PCIe bandwidth is much more important for that than having a 5090, where a 3090 or 4090 will get the job done.
Even if pure speed is your primary concern, you can tune a sparse 120B model (like Laguna) to run almost as fast as Qwen 27B on a 5090, and get at-least-good results.
It’s more finicky and involved, though. For sure.
Running an LLM on a 5090 is a task. Hybrid CPU + GPU inference is a hobby.