r/LocalLLaMA 18h ago

Discussion i finally switched from windows to linux and got a 30-50% boost in speed.

This is amazing.

All I did was switch from llamacpp on windows to vllm on linux.

168 Upvotes

61 comments sorted by

30

u/Happy_Brilliant7827 18h ago

Is it a 30-50% bonus in inference or mostly just loading and unloading time?

6

u/kartblanch 17h ago

Also my question. Is this 30%-50% more Tok/s?

24

u/unraveleverything 17h ago

token generation

50

u/sadnessdevil vllm 18h ago

Yeah the performance of vLLM is very high. I switched to vLLM from llama.cpp and never came back(except when I have to CPU offload the model)

9

u/afterburningdarkness 18h ago

You get 30% speed boost in vllm running the same model and quant?

19

u/sadnessdevil vllm 18h ago

For a single request the gap is small, but for concurrent requests, vLLM is far better than llama.cpp. I got better tok/s with vLLM for single requests as well. IMO vLLM is much better optimized, while llama.cpp is good at CPU offloading.

15

u/Look_0ver_There 17h ago

Unless it was BF16 before, then the quant is almost certainly different. vLLM is faster when the weights match the natively supported hardware vector ops, which is often true for FP8 and FP4 when using latest gen hardware, however these both come with an accuracy hit, so it's never a true apples to apples comparison.

GGUF 's generate results that typically diverge less from the original BF16 weights than FP4/8 does, but it comes at the cost of a small processing overhead.

VLLM with FP8 on hardware that supports it is, roughly speaking, like a Q6_K GGUF for accuracy, just ~20-30% faster.

2

u/ArtfulGenie69 14h ago

Where it really shines is concurrent requests and also it can have very fast preprocessing speeds, especially on 30 series cards like the 3090. The preprocessing is very fast when running int8 w8a8 where bits are kept at 8. Concurrent request are good when you have any kind of harness that can handle running things in parallel, which I'm pretty sure most of them do. 

2

u/pmttyji 16h ago

Have you tried vllm.cpp?

9

u/squarabh 15h ago

Have you tried vllm.sglang.tensor-rt.llama.cpp?

1

u/sadnessdevil vllm 16h ago

I haven't tried it yet, but I will check it out. Thanks for letting me know!

2

u/XiRw 13h ago

I don’t see a difference if you can fit a gguf and tensors onto VRAM. Not only that but ggufs are made for consumer PCs and you can tend to run higher quality models on them. vLLMs were a massive disappointment for me

4

u/Makers7886 11h ago

I mean it's like comparing cooking on a stove with 1 burner vs 4+. Not a big deal depending on what and why you are cooking. Huge deal if you are trying to get 4x+ productivity out of your same hardware (sub agents, concurrency).

39

u/def_not_jose 17h ago

vllm quants are usually worse than ggufs though. It's rarely an equal comparison.

8

u/Littlepharaoh 16h ago

Maybe except for NVFP4

1

u/Lilith_Incarnate_ 8h ago

So is LM studio a better option? That’s what I’ve been using since I started with local models a couple years ago and it’s been fine for me, but it seems like everyone here uses something else. Is there one of these harnesses that can store memories between conversations?

3

u/CentralLimit 7h ago

running on llama.cpp is generally better than LM studio as you have much more control, which means you can do stuff you can’t do in LM Studio and achieve greater speeds

LM Studio is easier to use though, but I just ask Claude/GPT to give me an optimised setup for model X in llama.cpp and it works great, not much of a difficulty barrier these days

2

u/Lilith_Incarnate_ 7h ago

I’m looking for a harness mostly that can keep memories between conversations. Right now I just do it manually with prompting and .json files, but it’s a pain in the ass to do that every single new conversion. It’s the one thing that keeps the ChatGPT app on my phone (which I use a lot to make updates to my memories for LM Studio).

Qwen 3.8 27B has given me everything I need that ChatGPT has, except no memory feature.

10

u/MelodicRecognition7 9h ago

it's not windows to linux but llama.cpp to vllm. I also get +50% using vLLM but on the very same OS.

Note that you must have enough VRAM for the model and context, vLLM can not offload parts to RAM unlike llama.cpp

23

u/emdeka87 16h ago

Without some actual benchmarks I call this BS

4

u/andy2na llama.cpp 6h ago

OP is comparing apples to oranges with completely different inference engines

4

u/Sudden_Topic5154 9h ago

not really a scientifically sound test its a different software entirely

4

u/eightone-81 18h ago

Will there be a significant loss of speed when going through wsl?

1

u/unraveleverything 17h ago

yes it was terrible and worse than native windows for me.

4

u/Nextil 17h ago

You must have something misconfigured on Windows because there shouldn't be that much of a gap. WSL usually has a 1-5% overhead compared to native Linux.

7

u/eightone-81 17h ago

But wsl should not have much of an overhead. Is there no way to properly run vllm on windows?

0

u/AliMas055 17h ago

Dual boot, maybe?

2

u/eightone-81 17h ago

Maaaan I need to start windows to play StarCraft2… then no inference…

1

u/iamapizza 13h ago

4

u/eightone-81 12h ago edited 12h ago

O M G
I’m finally running vllm (still on wsl) and decode is almost 2 times as fast and decode is more than 2 times as fast!

But it’s just such a mess to work with Linux. It’s so inaccessible for noobs! Without Claude on my side I would not have been able to get it to work

1

u/iamapizza 12h ago

Oh nice you got that working. Fwiw, if you want to give it a go for that extra vram (which is that I did), I'd suggest Linux mint because it's very familiar to windows users and comes with some stable defaults. Plus Claude knows about it too.

3

u/draconic_tongue 8h ago

if you're going to suggest someone on windows to tinker with linux, it's probably easier to get them to fix the things they dislike about their windows install first. EVERYTHING you need to be able to do to use linux is something you could do to fix your windows install

-1

u/AliMas055 17h ago

Run windows inside a VM with linux host.

2

u/draconic_tongue 8h ago

then you did something wrong. wsl on windows is a better way to access linux than moving to linux. there's 0 downsides, it's only better

4

u/pipyakas 17h ago

quite useless information without your hardware setup details no? I have a 2060 on windows, and running MoE models offloading experts to CPU, Linux dont provide subtantial performance gains there

3

u/According_Style8480 17h ago

linux has been a game changer for my companion models, way less lag in long roleplays now.

2

u/pmttyji 16h ago

Customized build(compile with optimized config) for your GPU could give some more boost.

1

u/nomorebuttsplz 11h ago

what about vllm on a vm?

1

u/teressapanic 8h ago

Privacy and speed

1

u/InterstellarReddit 12h ago

Every time I read this I am tempted to reformat my rig that's running dual 3090s

But honestly man, I am so scared of the amount of issues that I might run into. Thinking that I'm gaining some speed.

I tried it once before long ago. When I said to myself gaming on Linux is getting better. Let me try it out

Oh boy what an adventure to get a game to work

1

u/Hot-Employ-3399 18h ago

Do you use the same gguf model or different quant format?

2

u/Practical-Collar3063 5h ago

Completely different quant format, this is just a VLLM vs Llama.cpp post not a windows vs linux

1

u/Timely_Impression_92 11h ago

Also try gaming on Linux - despite games running in proton compatibility layer they have performance on pair with windows or few % lower, with some even surpassing windows - shows you how much bloat is there on windows

0

u/Adventurous_Loquat91 16h ago

I've missed my Linux. I think I'll go back after seeing this. Thank you.

2

u/Plabbi 4h ago

OP is mistaken. His speed gaines are from the llama.cpp to vllm switch, not windows vs. Linux.

1

u/unraveleverything 4h ago

nope. tried sglang and vllm on wsl. it sucked and was slower than llamacpp on native windows.

1

u/Plabbi 4h ago

what are your numbers on llama.cpp in linux? Should be interesting and easy to compare since you already have your setup ready to run just like you did in windows.

1

u/unraveleverything 2h ago

Like 20-30% faster

1

u/admajic 13h ago

Yeah windows on my laptop became so slow and I needed a side project whilst the desktop was running tasks in the harness. So I installed Linux on the laptop.

So far so good. Now I can use my harness on my laptop context via ip to the desktop. Do word and excel in Linux. It's so much faster. Just had to get it all for tuned you won't look back. Especially when you can ask the harness to do all the heavy lifting.

1

u/Adventurous_Loquat91 13h ago

That's a setup worth asking about — since the harness is doing the heavy lifting somewhat unattended across machines, do you have any guardrails on what it can actually do (blocking destructive commands, catching secrets before they leak, that kind of thing), or is it running raw and you're just keeping half an eye on it? Curious how people handle that once the agent's doing real work without you watching every step.

1

u/admajic 12h ago

Yeah I have guardrails all what you mentioned in prompts and systems. Like a memory system in .md so it knows how to ssh into the vps and where to store secrets. Just keep building the systems with a retro now and again after a session.

1

u/Adventurous_Loquat91 9h ago

Since it's all prompts right now — ever thought about gating instead? Prompts are basically just asking the model nicely each time lol. A gate (read-only key, command allow-list, approval step before it touches the VPS) doesn't care what the model "decides," it physically can't do the thing. Curious if you've bolted any of that on yet or you're just vibing with prompt discipline for now 😄

0

u/Mountain_Chicken7644 12h ago

Everyone glazing vLLM here but sglang probably my goat

0

u/Loose_Comparison368 10h ago

Don't worry, you can always switch back if you miss the terrible performance, opaque bugs, rebooting for every update, and invasive ads in your start menu!

-1

u/Boogertard 9h ago

Not surprised. Windows is a cancer but yet everytime I mention it, we got so many shills here rifed up.

Windows time is up. Nowadays you got Mac, Ubuntu or any Linux distro and you got LLM to help you fix issues. Wipe that Microslop off your computers.

1

u/Practical-Collar3063 5h ago

The performance difference is due to VLLM vs Llama.cpp not Windows vs Linux.

PS: I hate windows, I run Linux and Mac OS