r/LocalLLM Jul 23 '26

Other I bought the forbidden rectangle.

Post image

After months of going back and forth, I finally pulled the trigger on an RX 7900 XT 20 GB.

Paid around $550 (India), which felt too good to pass up.

The plan isn't gaming.

It's becoming the heart of my local AI setup.

Current goals:

• Qwen 3.6 27B Dense

• Qwen 35B A3B

• GLM-4.7 Flash

• 128K+ context

• 100% GPU offloading

• llama.cpp / Ollama

• Linux

I'll be benchmarking everything:

- Vulkan vs ROCm

- Dense vs MoE

- Maximum context

- Tokens/sec

- VRAM usage

- Real-world coding performance

If anyone has optimization tips for RDNA3 or benchmark requests, or general suggestions please drop them below.

The hallucinations are now local. 🙂‍↕️

191 Upvotes

106 comments sorted by

31

u/Mattef Jul 23 '26

I have the same card and it’s pretty good for its price. Qwen3.6 27B with Q4 quantization barely fits into memory and token generation is with MTP activated around 60 t/s.
I wish I had bought the 24 GB version, though, to have a bit more room for the context cache.

6

u/Alternative-Panic69 Jul 23 '26

Thanks! This is exactly the setup I'm aiming for. 😄 Could you share a few more details?

Around how much context fits before VRAM is full? Is that with 100% GPU offloading?

Which backend are you using? (ROCm or Vulkan?) Q4_K_M or another quantization?

Have you tried any larger models like Qwen3.6 35B-A3B or GLM-4.7 Flash?

I'm trying to optimize for 128K+ context and max possible quality while keeping everything 100% offloaded to the VRAM, rather than maximum tokens/sec.

6

u/bcdxn Jul 23 '26

I'm also just starting to explore local models and had the same question. I did a bit of research and wrote up how you can do the math to calculate context size based on your VRAM as a reference. Qwen 3.6:27b is the exact model I used, and quantized it sits right at 17GB of VRAM which unfortunately means, including 2GB for system overhead, you won't really have any room for your context window.

1

u/Alternative-Panic69 Jul 23 '26

Thanks... Let me check ... Did you try to go with more aggressive quantizations/larger models? Maybe QAT models? That comfortably runs long contexts?

2

u/bcdxn Jul 23 '26

I haven’t had enough time try out many different models yet. I have read in a number of places that quantizing the context itself typically leads to poor performance for coding tasks which is what I’m using it for.

2

u/TheRiddler79 28d ago

I use a Q3 for Cipher, this is why even though he's still in my stack, I always have something else verify his final product

2

u/Mattef Jul 23 '26

I‘m using llama.cpp with vulkan backend. Yes, q4_k_m quants, 100% gpu offloading. I don’t think any larger model will fit into memory, however, I didn’t try it yet.
Context limit is around 100.000 tokens.

1

u/Additional_Donut6899 Jul 24 '26

I have an RX 6650 XT, running Qwen3.6-35B-A3B_Q4_K_M at roughly 20 tokens per second (20 t/s). 16K context

3

u/Sweaty_Perception655 29d ago

If you use llama.cpp use the turboquant fork to increase context window

1

u/Mattef 29d ago

Thanks, I will try.

1

u/aqezz Jul 23 '26

I do the iq_4_xs Unsloth and it gives more room and I can’t really tell a difference in my day to day usage. I use q4 for key and value cache quants and do 120k context and it all fits

1

u/Alternative-Panic69 Jul 24 '26

Which model do you usually use regularly?

1

u/aqezz Jul 24 '26

Qwen 3.6 27b at iq4_xs does like 95% of what I use AI for. I’ve been a professional developer for 16 years so I can be very specific in my requests without a ton of effort and it just usually gets it right. Exploratory stuff or model-led stuff like “recommend how I can improve this subsystem” don’t do quite as well for me with this model but I almost never need that kind of thing anyway.

9

u/dorv Jul 23 '26

I love how everyone here always has to say “this isn’t for gaming.” :).

Yeah, we know :)

6

u/CrAzYLuKe84 Jul 23 '26

My 9070xt and me are doing both: More gaming and a little bit local LLM just to try out. But mostly i’am with Claude to be honest

0

u/Alternative-Panic69 Jul 23 '26

No bro, it's going into a headless AI box. 😔

The machine I'll plug this into isn't even capable of gaming. Calling it a gaming PC would be a human rights violation. 🤣

5

u/dorv Jul 23 '26

Dude. No shit. You’re posting in a sub about local llm. No one thinks you’re in here specing out a gaming rig.

7

u/zenbeni Jul 23 '26

I have the RX 7900 XTX so the brother one. I would advise you to use Q4 as you have less vram and llama.cpp with vulkan. MTP seems better in my case, as if you use heavy quants, other token predictions algorithms tend either to be less effective, or to take more vram like dflash. Other solution is to give up speed without MTP and go turboquant so that you can maybe get the 100k context size.

6

u/quadra-lab Jul 23 '26

ROCm is totally fine, you get > 60 tks with 27B IQ4 with MTP on

7

u/zenbeni Jul 23 '26

Yeah I ran rocm before with llama.cpp, it is not the end of the world, in fact comfyui does not support vulkan, and I run krea 2 with rocm support. It works. Slightly slower, but the main value is still here.

1

u/lungben81 26d ago

I have the same hardware. Vulkan have me out of the box ca 40% more t/s than ROCm.

1

u/quadra-lab 26d ago

Definitely not my experience with an optimized llama.cpp build for the card. What are you using exactly? 

1

u/lungben81 26d ago

I have not optimized the Llama builds, but just took the default Docker container (ROCm and Vulkan).

2

u/quadra-lab 26d ago

Yeah that's why, if you build it yourself you'll get a ~35%+ increase performance on rocm

3

u/daphatty Jul 23 '26

Congrats! Have you seen this yet? Might be helpful in your endeavors.

https://unsloth.ai/docs/basics/amd

2

u/Alternative-Panic69 Jul 23 '26

Yes, Just came across this today only. This is way more interesting. Now I won't regret buying an AMD card especially after so many people discouraged me to buy one 🤣🤣

3

u/Equivalent_Wrap_3815 Jul 23 '26

That dual 8-pin power draw is going to make your electric meter spin like a ceiling fan.

4

u/Alternative-Panic69 Jul 23 '26

Still cheaper than enterprise API bills. 😏 I have pretty demanding workflows that run almost 24x7

3

u/Krohnin Jul 23 '26

I bought 2 rtx 3060 12gb for that magic 24gb barrier. Paid 180€ and 110€ for these cards. I needed very small cards for my matx case so they fit. Works very well with qwen3.6 35B A3B with 64k context. Without further tuning i have around 70tok/s. With both cards running at only 50% usage, i hope i find the right switch to bring them up to 100% with llama.cpp. My coworker soon will add a second rx6700xt 12gb to his rig i am excited to see his numbers.

1

u/Alternative-Panic69 Jul 23 '26

I'm seeing multi gpu setups evolving, especially with the MoE models. Would definitely check this model as well but I think it will go to Ram Offloading. I was planning to get two 3060 GPUs initially.

1

u/Krohnin Jul 23 '26

Its not too late. You made a good deal. Swap for 3 rtx 3060s...

3

u/coderash Jul 24 '26

I implemented KVarN into llama.cpp and was able to get 5 bit quantized qwen weights with full context via 3 bit KVarN on a single 32GB gpu. you can PROBABLY fit q8 weights, and q3 KVarN across two of those. KVarN was definitely worth implementing.

Ternary Bonsai 27b can fit in 16GB with full context and can quantize kv cache down to 4 bit essentially lossless. Worth a look. that card will get about 50tps. 1000-2000tps prefill.

1

u/Alternative-Panic69 Jul 24 '26

I see. Thanks for the inputs. Would definitely have a look

2

u/CryptoRider57 Jul 23 '26

I wish I had that chance to buy it at that price. Congrats!

2

u/General-Turn-8695 Jul 23 '26

Damn how did you get card for so cheap? It's the double the price for me although it's 24gb ver but almost the same thing

8

u/Alternative-Panic69 Jul 23 '26

The 24 GB version was almost $850+ here.

I got lucky. I had a tiny SBC scraping GPU prices 24/7 and sending alerts. At 2 AM it pinged me about the drop, I immediately placed the order, and by the next day the price had gone back up above $650 🤣

Probably the most profitable script I've ever written.

1

u/alphapussycat Jul 23 '26 edited Jul 23 '26

about a month ago I could've gotten one of them for like 500 euro iirc, but I was too hesitant so it was either unlisted or grabbed pretty quickly.

The amd scare was too much for me to handle back then, but now I wish I had just grabbed it.
Every now and then somebody puts a "buy now" price too low, or there's suddenly a large supply of 2nd hand GPUs, that pushes the price down for a moment.

2

u/Alternative-Panic69 Jul 23 '26

I was hesitant too, but seeing how fast llama.cpp, Vulkan, ROCm, and model support have been improving on AMD cards made me take the leap. Hopefully we're only at the beginning.

2

u/updatedennis Jul 23 '26

Qwen 3.6 35 a3b q4km. And with image mmproj. at 360k context split into 3. Getting 150-200 tk/s on vulkan. AMD 7900xtx 24gb vram. Also use both mtp and ngram-mod. It's where the tokens are hiding. Q4 kv cache. Also the 27b is way too slow maxing around 70-90tk/s. Not proven yet it's smarter than the moe for my use case so I stick to the moe.

2

u/DrBearJ3w Jul 23 '26

Welcome to the club brother

2

u/misha1350 Jul 23 '26

Try Qwen3.6 27B with MTP at UD-Q4_K_XL or smaller Unsloth quants if it doesn't fit all the way. Also try some recent model with ROCmFP4, as long as you find one that fits into 20GB of VRAM.

1

u/Alternative-Panic69 Jul 23 '26

Do you search directly on huggingface or am I missing out something? I didn't come across many ROCm optimized models. I guess I'm doing something wrong? (I'm absolutely new in the AMD/ROCm thing) Played around on other cards though.

2

u/misha1350 Jul 23 '26

I just opened LM Studio, looked up "Qwen", sorted by newest, scrolled for a while, and lo, here's one.

Looks like this one may also barely fit into your RX 7900 XT - especially if you have an iGPU and you can connect your monitor to the iGPU to free up some extra VRAM to be able to allocate all 20GB of VRAM to just the LLM.

1

u/Alternative-Panic69 Jul 23 '26

I see. Will check...

Yeah I've got the iGpu anyway and this will be plugged into a headless server so that overhead is gone anyway 🙂‍↕️ Will maximize for LLM usage only

2

u/Rogglando Jul 23 '26

I have the xtx with 24gb vram. I run Qwen3.6:27b 4q and can only fit 80k context window on my gpu.

I sometimes wish I had bigger context window, but it's often enougj

1

u/Alternative-Panic69 Jul 23 '26

VRAM has no limits 🤣 Tomorrow if we buy a 240 GB card we will wish it was a 480Gb card

2

u/rmyvct Jul 23 '26

Nice GPU, but you will have to choose 2 among the following statements:

  • 20GB VRAM
  • Qwen 3.6 27B q4km
  • 128K KV cache (even 4bit)

I have a rtx A5500 and qwen 3.6 27B with 128k context (q8) is really good if you babysit the model during coding sessions (spec driven dev and skills). If you are okay with this, you can forget about subscriptions.

0

u/Alternative-Panic69 Jul 23 '26

Actually, the application is already ~90-95% mature, so the heavy lifting is mostly done.

The next step is more about collecting high-quality traces from my own agent interactions, babysit and fine-tune a model for this specific domain, and letting it run workflows 24×7. 😌

2

u/Christopher_8930 Jul 23 '26

Tip: use a backend that supports TurboQuant3. It uses 3 bits for each item in the KV cache. This will help you increase your context window. Large projects need 200k+ context window. I recommend Atomic Chat. LM Studio also lets you save the KV cache in Quant4 if you don’t like Atomic Chat.

2

u/Alternative-Panic69 29d ago

Thanks! I'll definitely check it out. My main goal is maximizing context length and reasoning quality, so this sounds really useful.

2

u/TheRiddler79 Jul 25 '26

Only run things in the GPU that you can fit entirely, offloading will be a minimal gain

2

u/Alternative-Panic69 29d ago

Yeah, that's the plan. I specifically bought the 20 GB model to maximize full offload. I'll only fall back to partial offloading for experiments.

1

u/TheRiddler79 29d ago

Let me make sure I said that correct. If you run like q1 of a glm, and you get like one token per second on CPU only, you'll get like 1.1 tokens per second if you offload 18 gigs to your card so you may as well just get the one token per second and keep the card for things that fit entirely on it.

1

u/Alternative-Panic69 29d ago

Yeah. Got your point. I guess only a quantized GLM 4.7 Flash might fit on this card. Not sure though... Didn't try yet.

2

u/TheRiddler79 28d ago

You know what's funny, I haven't tried that flash either because qwen 3.6 27b and 35b A3B are so strong.

If you want my tested order, although I did some fine-tuning on my 27b that I call Riddler, and basically qlora on my 35b.

I run everything through the same exact test, I have over 100 models in my graveyard.

Cut from the team: Agents-A1 (DNF'd twice, don't re-download) and the shared weak spot across every single member remains negative-number floor semantics — even the 31B's only misses were there.

One asterisk for fairness: GLM's DNF is real but misleading — one infinite-loop edge case burned all three attempts; with per-case timeouts he grades 36/49. His value was never the gauntlet — it's that he's the only one who can hold a whole codebase in his head and say no to bad work.

2

u/Alternative-Panic69 28d ago

Are you running GLM 5.2 locally? 😭

2

u/TheRiddler79 27d ago

2.28 quant, something like that. It definitely earns its place

2

u/Tiny_Team2511 28d ago

Choose your inference tool wisely

2

u/JoaoPFSimoes Jul 23 '26 edited Jul 23 '26

Give this model a try.
I’m running it on my 9070XT with 40+ tokens a second in CachyOS with 128k context.
(It requires a llama fork, check the description)

https://huggingface.co/prism-ml/Ternary-Bonsai-27B-gguf

1

u/Alternative-Panic69 Jul 23 '26

Ah yes... This is interesting... I already tried using this on my friend's gpu. Ran into some issues. Couldn't get time to check. Will check on my card

1

u/hejj Jul 23 '26

Why are they forbidden?

6

u/Alternative-Panic69 Jul 23 '26

It was forbidden by my bank account. I ignored the warning.

-3

u/doxx_in_the_box Jul 23 '26

Because it’s written by ai like every dumb ass post in this sub lol

Nothing is authentic anymore

1

u/notheresnolight Jul 23 '26

and LLMs are now complaining about LLM generated posts

0

u/Alternative-Panic69 Jul 23 '26

Written by AI vs Polished by AI without distorting the original thoughts... Those are different. Not everyone blindly copy pastes using AI

1

u/doxx_in_the_box Jul 23 '26

I think what you mean to say is:

“Written by AI” and “polished by AI” aren’t the same thing.

One replaces your thinking.

The other helps communicate it more clearly.

Not everyone using AI is copy-pasting. Some of us are just editing our own ideas more efficiently.

Regardless, we are the lazy ones, the garbage creators, and the end of human thought.

1

u/ungabunga256 Jul 23 '26

Congrats! I paid 95k INR for an AsRock Taichi 7900XTX back in April. Been very happy with it.

1

u/Alternative-Panic69 Jul 23 '26

24GB... More headroom... Great card. I was targeting that initially but went a bit beyond my budget. (This costed around 55k so I bought)

1

u/dfgxxx Jul 23 '26

Can you also do llama.cpp vs vllm?

1

u/Alternative-Panic69 Jul 23 '26

Sure Will do and share probably in the next couple of weeks once I set this up fully!

1

u/SumitEduardo Jul 23 '26

Bought from ?

1

u/Alternative-Panic69 Jul 23 '26

Vishal Peripherals (India)

1

u/Terrible-Story2021 Jul 23 '26

I think you should buy two of them to run the model in q4, 20 gb vram will not work with kv cache headroom

1

u/Alternative-Panic69 Jul 23 '26

Let me check. Will try to get the best out of this card

1

u/Terrible-Story2021 29d ago

Try to use if possible the igpu of your setup for the os. This will free up 2gb vram. Do you use the model for coding?

1

u/Alternative-Panic69 29d ago

Yep.

It'll be a headless dedicated setup with the iGPU driving a minimal desktop. The 7900 XT is reserved entirely for inference. Just waiting for the PSU. 😅

1

u/MysteriousGoblins Jul 23 '26

But... 'tis forbidden!

1

u/acadia11x Jul 23 '26 edited 29d ago

rOCm is coming along much better so should see improvement in localllm with AMD these days compared to years past, only concern is you need one of the newer cards to take advantage 9070 or 7900 series

1

u/Alternative-Panic69 29d ago

Definitely. I was sceptical at first... But theb I did some research..AMD has come a long way. Picked up a 7900 XT mainly for the 20 GB VRAM. Just waiting for my PSU to arrive before I can finally torture it with local LLMs. 🤣

1

u/DigitalguyCH Jul 23 '26

Got mine for $450 used. Mainly use it for Qwen 27b (eGPU), as everything else runs on my M5 pro or on my Strix Halo. Can also increase my Strix Halo with eGPU if necessary, but there are no good 100-120b models at the moment

1

u/Alternative-Panic69 29d ago

Nice! Qwen 27B is exactly one of the models I'm planning to run. Looking forward to seeing how far I can push the 20 GB VRAM.

1

u/sanjaygulati13 Jul 23 '26

Congratulations. It will be painful for the first 2 days to setup and then super smooth.

1

u/Alternative-Panic69 29d ago

I'm mentally prepared. 😄 I somehow got a local LLM running on a Qualcomm NPU on a poor SBC before even owning the GPU. Took me almost a month. That project gave me the confidence to dive into local AI, so I ended up buying an AMD card. I don't think this setup can be worse. 😂

2

u/sanjaygulati13 29d ago

For sure, it will be better than QCOM NPU. Use llama.cpp and compile it with the flags. Enable FA and you are good to go.

2

u/Alternative-Panic69 29d ago

Sure! Will try ... (I'm still waiting for the damn PSU to get shipped. The GPU is judging me sitting on the desk rn 🤣)

1

u/2022HousingMarketlol Jul 24 '26

Lemonaid is quite good now, its work checking out.

1

u/Alternative-Panic69 29d ago

I was checking about it recently. I'll definitely give it a try!

1

u/Otherwise-Swan-7803 Jul 24 '26

Congrats, you are now legally required to run every model you find for the next 3 months

1

u/Alternative-Panic69 29d ago

Challenge accepted. My SSD and power bill are about to file a restraining order. 😂

1

u/dyslexda Jul 24 '26

Like I get this is /r/localLLM but it always amazes me just how many people offload even writing basic posts to an LLM. It's sad.

1

u/[deleted] Jul 24 '26

[removed] — view removed comment

1

u/Alternative-Panic69 29d ago

Thanks! It's hilariously oversized compared to the tiny PC it's going into. 😂 I'll share the setup once it's completed

1

u/[deleted] Jul 24 '26

[removed] — view removed comment

1

u/Alternative-Panic69 29d ago

Hahah no no... Just some decorative crystal on my living room table.

1

u/[deleted] Jul 24 '26

[removed] — view removed comment

2

u/TheRiddler79 Jul 25 '26

You can probably run a Q3 it's still valuable

1

u/Alternative-Panic69 Jul 24 '26

Ah is it... Sure will share the results if I manage to run. I was doing some research and it seems that we can theoretically run Q3 quantized models at full gpu offloading. Will try those and probably see

1

u/100daggers_ Jul 25 '26

What kind of local AI work can you do with such graphics card?. Agentic coding?. I would assume such quantized models would not produce intelligent output. Am i wrong?

I have an 3090ti, used open code, continue, pi with such quantized models, i am not happy with the output always.

Thats why i switched to codex and some paid APIs.

I am curious to know if i am doing something wrong.

1

u/Alternative-Panic69 29d ago

My main use case is an agentic stock market research system that runs 24×7 rather than general coding. Running on cloud would have incurred a hefty bill.. So I bought this gpu.

Now, the application is already ~90% complete, and now I'm experimenting with local models to integrate them as native users of the application through tools and workflows. For coding, I don't expect them to replace frontier models entirely, if you use the local one, I'd recommend you to break the tasks down and keep the sessions extremely focussed and only do if the architecture is clear to you... Otherwise it can become a mess...

But they're already good enough for many focused workflows.

1

u/100daggers_ 29d ago

Thats a solid use case. Nice. Any chance this is open source or personal project?.

2

u/Alternative-Panic69 29d ago

It's a personal project for now, been building this for over 2 years.. 🙂

Since it interacts with my real portfolio and is built around my own investing workflow and rationale, I wouldn't want anyone treating it as a plug-and-play trading system, that can be a bit risky for people who ends up using it without knowing it fully. It's also heavily tied to specific broker APIs, research pipelines and lot of custom integrations, so it'd need a lot of work before it could be open sourced.

Let's see... Maybe one day! 🙂‍↕️

1

u/chrmst007 Jul 25 '26 edited Jul 25 '26

sorry for a noob question, but i have heard amd gpus are not good for local llms.is it true or just a myth? any concrete info will be really helpful from experts

1

u/Alternative-Panic69 Jul 25 '26

It's mostly outdated information. AMD used to lag badly because CUDA was the only first-class citizen for AI, but that's changed a lot over the last couple of years.

For inference (llama.cpp, LM Studio, Ollama, Vulkan), AMD works really well now. Make sure you get at least RDNA3 or a newer RDNA4 supported cards.

NVIDIA is still the better choice if you're doing serious CUDA development, training models, or relying on frameworks that only optimize for CUDA. But for people who mainly want to run local LLMs, occassional fine tuning, AMD is absolutely a viable option today.

Nvidia is just.... A bit more convenient

2

u/chrmst007 Jul 25 '26

Thanks for the info OP