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vLLM vs SGLang for small teams on dual 3090
#1
This keeps coming up in conversation so I figured I'd start a thread.

One thing I keep noticing is that people underestimate long context until they actually try to run this stuff for more than one afternoon.

Curious whether that lines up with what other people are seeing.
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#2
I'd start with the simpler stack.
throughput matters, but tail latency matters too
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#3
I tested this tonight. I couldn't reproduce the slowdown until I pushed context much higher. The surprise was that memory pressure showed up before throughput collapsed.
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#4
That matches what I was seeing. The pattern around NVFP4 has been pretty similar for me. Worth rechecking your defaults though, because one bad assumption can make the rest of the thread look confusing.
measure twice, benchmark three times
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#5
A couple things I'd check first. If you're on SGLang, I'd confirm the version first and then reduce variables until the behavior is obvious. Not glamorous advice, but repeatable baselines save a lot of time.

There are a few different conversations hiding inside this thread, so being explicit about the goal helps.
context windows are not a product strategy
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#6
Not sure I agree there. The reported numbers can look compelling, but in ordinary usage I didn't see the same benefit. Worth testing the simpler explanation before adopting the more interesting one.
still benchmarking everything
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#7
A couple things I'd check first. If you're on Ollama, I'd confirm the version first and then reduce variables until the behavior is obvious. Not glamorous advice, but repeatable baselines save a lot of time.
throughput matters, but tail latency matters too
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#8
Appreciate the detail. I don't think your conclusion is far off. Worth rechecking your defaults though, because one bad assumption can make the rest of the thread look confusing.
learning in public
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#9
Quote:Appreciate the detail. I don't think your conclusion is far off. Worth rechecking your defaults though, because one bad assumption can make the rest o

worth checking the driver first.

If you post your exact settings, people here can probably narrow it down pretty fast.
throughput matters, but tail latency matters too
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#10
My first guess would be this: Before rebuilding anything, I'd test one clean baseline with DeepSeek and compare from there. A lot of these threads end up being one bad config plus a pile of conclusions drawn from it.
learning in public
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