Can an RTX 5090 run Qwen3 30B A3B?

In practice

It fits, with very little to spare. Qwen3 30B A3B at Q8_0 needs 30.99 GB and the GeForce RTX 5090 offers 31.2 GB, a margin of 0.21 GB. That is enough to load it and run at about 190 tokens per second, and not enough to be relaxed about.

Three things take the margin away. A longer window is the first: at 16k the cache alone grows by 0.75 GB. Another program holding VRAM is the second, since a browser with hardware acceleration can take a gigabyte. And a runtime that places layers conservatively is the third, which Ollama does. Store the cache at 8 bits and close the other programs before you load it, and go down one quantization if it still will not.

Reading a 4,000-token prompt, roughly a long email or a few pages of text, takes under a second before the first word appears. That part is limited by compute and not by bandwidth, so it follows a different spec from the writing speed.

The numbers

Qwen3 30B A3B has 30.53 billion parameters across 48 layers, of which 3.34 billion are read for each token. The GeForce RTX 5090 has 32 GB of VRAM at 1792 GB/s, of which about 31.2 GB is left for a model once the operating system has taken its share.

9 of the 9 levels fit entirely. Levels marked degraded are listed for completeness, not as advice.

How long a conversation it holds

Memory rises with the length of the conversation because the attention cache keeps a key and a value for every token. At Q8_0, the longest window that still fits on this device is 8k tokens. Setting the window to what you need and no more is the cheapest way to buy back memory.

The settings we would use

llama-server -m <model>.gguf -ngl all -c 8192 -fa on -ctk q8_0 -ctv q8_0

The cache is stored at 8 bits because headroom is under 1 GB. That halves it for a small quality cost.

In Ollama, set OLLAMA_CONTEXT_LENGTH to the window you want, run ollama ps while the model is loaded and check that the processor column reads 100% GPU. If it shows a split on a model that fits, the Ollama guide shows how to fix it. The llama.cpp flags guide explains each option above.

What else an RTX 5090 runs well

For comparison, these are the other popular models that fit this device at a sound quantization, best pairings first.

The same model on nearby hardware

Memory decides whether Qwen3 30B A3B loads and bandwidth decides how quickly it answers. Here is what a step down, a card with the same memory and a step up do with it.

Wait for the first word21 ms

Then writes at190.2 tok/s

Whole answer931 ms

YouWhy does my model use more memory when the conversation gets longer?

Model

Simulated from our estimate at a 512-token question, not a recording. Assumes nothing else is competing for the GPU.

Questions people ask

Keep going

Everything the GeForce RTX 5090 runs, the full breakdown for Qwen3 30B A3B, how the numbers are made in the methodology, or a different pairing in the calculator.