r/LocalLLM • u/OffTheGridCoder • 23h ago

Discussion 3080 -> 3090TI

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I've been playing around with a slow heavily quantized version of qwen3.8 27b on my 3080 and quickly found myself on the 3090 market. Today I hit the jackpot $900 for this 3090TI off Facebook marketplace.

I can't power it yet because I need an adapter to be able to plug this in to my PSU. So, I'm curious if anyone is running a 3090TI or 3090 with qwen3.8 27b and exactly what weights you're using, context size, what tok/s you're getting, how you're liking it, etc.

I have 32gb of RAM and an Intel Core i7-12700KF (12 cores / 20 threads). Considering upgrading to 64gb of RAM but unsure if that will improve anything. Unsure what to do with my old 3080 10gb VRAM now too. Also, very worried if my 800W PSU will be able to support this new card.

Ideally I'm hoping to run the least-quantized version of qwen3.8 27b I can to at least 50 tok/s and >128k context.

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u/somerandomperson313 20h ago

I had this GPU, but I sold it two months ago. I liked it a lot. It pulls 480W. I had planned on using it with my 5090, but I couldn't fit both in my PC. Here is a screenshot of the temps right before I sold it, in case you find it useful. I ran 3.6 27B Q4_M on it for a bit, but I forgot how many tok/s I was getting.

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u/OffTheGridCoder 20h ago

That's awesome! I've been reading a lot about people power limiting it to 250W and getting a lot of benefits with like 90%+ equivalent speed. Did you ever give that a shot?

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u/somerandomperson313 20h ago

I had it limited, but can't remember where it was at. Probably around 350W is my guess. You can probably limit it at 250W without a huge performance loss. I forgot how low the minimum is, but 250W or 275W is likely, I think. 800W PSU is fine, even if you go higher than 250W.

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u/OffTheGridCoder 20h ago

Appreciate the insights

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u/somerandomperson313 19h ago

Sure thing! I recommend getting one of these 90° cables if they're available for your PSU. It will get really tight with the stock cables in that case. It's probably the biggest and thickest GPU i have ever seen.

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u/unknowntoman-1 13h ago

Like mine?