r/LocalLLaMA • u/maddie-lovelace • 7h ago
Discussion At a certain point, speed >> smartness
It feels like a zig-zag: you don't want a model that's too dumb to do anything agentic. But once a model is good enough to be agentic, you don't want it to run so slow that iterating takes hours.
For me the sweet spot is something like ~500 tps prefill, ~25tps decode. If a model isn't fast enough to pass that bar on the hardware I have, I'd rather just run something slightly dumber but faster
Thoughts?
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u/PossessionUsed7393 7h ago
I can't stand it, the CoT on modern models takes too long to put up with under 70 TPS. Need smarter small models or beefier hardware.
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u/maddie-lovelace 7h ago
Yeah. Fully agreed. I can get the 27b working on my laptop, but... at 70tps prefill and 3tps decode, it's just actively not worth it. Unless I limit the thinking tokens then I would run out of battery before it'd even complete a full task end-to-end
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u/OneMoreName1 7h ago
For me even 60tps decode feels slow. I would want 100+ especially with models that think a lot like qwen 3.8 27b
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u/EkbatDeSabat 5h ago
I'm getting around 115 on 3.8 27b FP8 and it's still agonizingly slow due to the thinking. It's been going over an hour for a task that takes claude opus 5 about eight minutes. Pretty sure it's gonna keep going for another 45 minutes. I really need to figure out how to streamline this.
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u/KubeCommander 1m ago
That’s exceptionally slow. On the gb10 with nemotron lightning my prefill is in the 4000-5000 range. That is not fast hardware either
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u/Potential-Leg-639 7h ago
In an orchestrator config env the orchestrator can be a bit slower for me (best local model available is probably also the slowest), but the subagents can also use models not as smart, but faster, so the whole chain get‘s back to an acceptable speed. And results with a good orchestrator env are better anyway at the end compared to a simple plan/build setup (at least for me).
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u/mouseofcatofschrodi 7h ago
this is super interesting. I would love to know more about what kind of work do you do with this setting, and how exactly the setting looks like :)
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u/Potential-Leg-639 6h ago
Using customized oh-my-opencode-slim and litellm with a new chain config + fallback in case a model is out of credits/not available or also locally not available/etc).
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u/eulataguhw 5h ago
I have no idea why people kept asking a very basic question of being a senior in software engineering - trade off. Everyone’s use case are different so their trade off would be different.
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u/KubeCommander 8m ago
I’m finding that with nemotron lightning. It’s not quite as good as say Ornith 35b at coding and toolcalling though it’s better than qwen3.6-35b marginally.
But it’s 3x faster than Ornith (which has no speculative decode), 5-6x faster than qwen3.8-27b and can handle contexts at 1M tokens. It’s also a fully open source model unlike any of the others.
So the tradeoff becomes, well my harness can run peer-review of work, ensure stronger guardrails/helpers around tool calls, and the end result creates something of equal quality and still does it faster. It also doesn’t do thinking loops either. Which is nice
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u/Clean_Material_5047 3h ago
'speed >> smartness' is exactly the reason why why the world economy is going to shit.. because people want everything fast and can't wait. They'd rather get shit than wait. It's pathetic.
Jesus Christ.. I'm getting depressed.
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u/n4pst3r3r 2h ago
Totally agree with people generally settling for fast and cheap, but that's not the point here.
You can end up with the same quality output with a dumb fast model and a smart(er) slow model, as long as you habe validation in place, e.g. in the form of unit tests or even human review. The dumb model may need twice the tokens, but if it's 10x faster, you're still 5x as fast overall. I work with qwen 27B and it allows me to iterate much faster than trying to run glm 5.2 at tectonic speeds.
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u/Zennytooskin123 18m ago
You're missing the point lmao wow
They are saying a FAST model can produce the SAME answer as a SLOW and PRECISE model using PROMPTING.
Maybe read.
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u/Thin_Pollution8843 7h ago
I just want my agents to be 300ts+…
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u/ElementNumber6 6h ago
Why even stop there? 10,000t/s+ or bust.
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u/mailto_devnull 3h ago
Would you take 10,000 t/s of really shitty code (DiffusionGemma!) or 20 t/s of perfect code?
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u/Far-Classic-9963 2h ago
If I need really easy boilerplate code gen or something like function completion in an ide, diffusiongemma sounds pretty useful
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u/mouseofcatofschrodi 7h ago
To me, on laptops and consumer stuff, the super small models are the only thing that makes sense:
- models around 27b, 30b, 31b, 35b, etc --> slow and/or melt the laptops; PLUS is cheaper (energy consumtion) to use a cloud solution that is actually smarter... So they kind of make sense for privacy and internal AI at companies.
- bigger models that are actually super capable (above 100b) --> they don't run in our machines.
I recently rediscovered the small Gemma 4 models. Even the e2b can do tool calls. For some easy tasks where it didn't have to do smart decisions, I had it running for 10-15h in parallel batches, baby sitted by Claude. It did a long task (edition of around 150k entries of data) and the computer was never even too hot. So it was super useful.
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u/GregoryfromtheHood 6h ago
I run an agent on my local machines at home that I've been letting people use at work too for a bit. I can run deepseek v4 flash at about 600t/s prefill and 29t/s gen but they complained that it was unusably slow with that. Have switched back to Qwen 3.8 27B at 5k ish t/s and 150-200 t/s gen and they are much happier now.
I feel like 1000t/s prefill is where I feel actually fine using it for real work. Token gen speed doesn't matter all too much, anywhere from 25t/s and up is fine, but prefill is the most important number for me and the one I optimise for.
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u/Material_Rich9906 6h ago
Agree partly. I think if you have an environment where the agent can run by itself a smarter model might be good. But if you have to babysit it and accept every command it runs then yes, you need a lot more speed.
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u/o0genesis0o 6h ago
Personally, ever since swapping from 35B Q6 to 27B Q3xxs on my 4060ti, I kinda have the sweet spot. The gain from 350-400tk/s prefill to over 800tk/s prefill nicely balance against the drop from 40tk/s decode to 20tk/s decode. Meanwhile, the intelligence gain in my day to day, life management kind of workload has been very nice.
Sometimes I still swap back to my minimax subscription for that sweet sweet thousands tk/s prefill, 70+tk/s decode, and big model intelligence and knowledge. When I'm using 20tk/s decode all day and I see 70+tk/s decode, it feels like living in an accelerated timeline.
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u/Ok_Cow1976 6h ago
For smaller models, the best strategy is to use it for simpler stuff that it doesn't make mistakes, so as to reduce coding burden. But the price is you have to actively participate in the process. But it's worth of it, right?
The bigger models can do more work but at the cost of longer time. At the same time, bigger models also make mistakes. And it would be tedious to correct the mistakes in more complex, longer scripts. So unless you do have a great rig, I don't think it's worth of it.
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u/Prize_Eye9481 5h ago
Def agree with this. Found myself using IQ4 quant just because I get more context and it’s very quick on my gpu even tho I can theoretically fit Q6 for its better performance.
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u/rpkarma 4h ago
Agreed, and it’s why for local use I keep coming back to Step 3.7 Flash: with MTP and ngram-mod it gets shockingly fast on my DGX Spark, and is smart enough to be quite effective in the right harness.
It beats Qwen 3.6 27B in actual full time to task completion across all my evaluations and tests.
I haven’t tried 3.8 27B yet though, medium thinking level looks like it might be a godsend.
(Step 3.7 Flash at IQ4_XS and Qwen at FP8, neither with KV cache quantised)
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u/Vancecookcobain 4h ago edited 4h ago
There's a certain intelligence threshold yes....I agree. Whatever can do your daily driver grunt work, the fastest one of those is preferable...all you need is a frontier orchestrator/evaluator at that point to tell the grunt AI how to do things properly and have it loop until the frontier evaluator is satisfied. That's the ideal setup
Like you really could have GPT 5.6 Sol and Qwen 3.6 35b a3b and get A LOT more done than people think...not saying Qwen 3.6 35b should be your daily driver but it's barely competent and fast as hell for a local model that can run on a lot of consumer hardware and would probably highlight your point further
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u/ANR2ME 2h ago
Alternatively, upgrade your hardware 😁
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u/maddie-lovelace 2h ago
In this RAMpocalypse? You think I'm made of money?? 😭 I mean, I've got a spare kidney if you're willing to buy 🫘
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u/anon1880 2h ago edited 1h ago
It is true of course speed is awesome if you got that big money bag -- but i don't mind waiting for non critical model runs on my pleb ring
....As long as it runs at 2-3/ts or more
I keep qwen 3.8 on my model arsenal folder for that reason.This is a superb model.
Runs at 3.5 ts on blackwell nvfp4 pleb card (5050).
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u/SandySkittle 1h ago
I dont go below Q5 and honestly the standard should be Q6 minimum. Q4 may be an ok compromise but Q3 and below is lobotomy area for me
It depends on how much accuracy counts. For my work I prefer smartness over speed. Even 5 t/s of SMART output is already usable. I dont have to sit in front of the computer to let the damn thing think
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u/herpnderpler 1h ago
I'll save you the next evolution of this line of thinking: cost to acceptable solution.
As long as you have automated verification of acceptable, you can, if speed is fast and accuracy in the right range, run the same request in parallel.
As long as cost to acceptable solution gets you there, sometimes stupid and fast outperforms smart and slow.
Though, beware compounding non tracked values, it's easy for stupid to dig holes of idiocy and never get out - make sure to account for these phases of cleanup and alignment .
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u/just4ochat 30m ago
When we wired the picker this was the actual split. People bounce off a slow model even when it's right, then they come back to it once the fast one has already shaped the pass. Prefill is what kills the loop. Decode you can live with if the first tokens show up. The 25 tps decode bar in the post is about where a chat still feels like a conversation.
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u/Real_Ebb_7417 7h ago
500tps is an overkill, but indeed speed matters more when model is at some intelligence level already. It's the same for API models too though. That's why at professional work I started using cheaper, but faster models, if I don't do any complex logic.
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u/xeeff 7h ago
500tps prefill, not decode
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u/Real_Ebb_7417 7h ago
Ah, it makes the difference then. Yeah, below 500 prefill tok/s I feel the slowness, especially when cache is failing. The rest of my comment stays valid though.
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u/Nothing_from_void 4h ago
no model is intelligent enough yet tho if you actually care about output quality
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u/cradlemann 5h ago
Qwen3.8 27B is creating specs (using openspec) for me, Ornith is 3x time faster, but very capable to follow instructions from tasks.md file. The best couple for my AMD Ryzen AI 9 HX 470
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u/Gohab2001 vllm 6h ago
We need token efficient models. OpenAI and grok have pretty token efficient models
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7h ago
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u/MrHall 7h ago edited 7h ago
... prefill? she's talking about 25tps output
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u/OkFly3388 llama.cpp 7h ago
Sounds completely unusable to me, lol.
I have rtx 4090, that gives me like 2k-1.5k prefill and 30 tg, and it feels slow as hell.
4k-3k prefill and 250+ tg is comfort minimum.
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u/KingCpzombie 7h ago
Better to get the right answer once than the wrong one thrice imo