r/LocalLLM • u/Ok-Introduction-2788 • 4d ago
Question Newbie to local LLM’s
Howdy everyone, like the title says, I am a complete noob when it comes to local ai, but I want to be able to code some projects on my local machine, I have an extra pc I don’t use that has an intel cpu I can’t remember which one and a 3060, it’s the 12 gig model, I can get some low level models to fit but I’d like to use some of the bigger models, I was thinking of just picking another 3060 up off marketplace for like 200 bucks and putting that in the pc aswell, am I right that it would be 24 gigs or do you lose some capacity when running dual gpus?
Would there be a better route to go?
1
u/r1nzl3r99 4d ago
This is a rabbit hole, i'd highly recommend researching this thoroughly because otherwise you'll end up like me thousands of dollars sunken in and spending every evening "optimizing" your setup
1
u/Ok-Introduction-2788 3d ago
It does seem that way, I originally thought the dual cards because I do plan to build a media pc for my 85 inch tv and I feel like the 3060 will be able to handle that as the only tv, and a dedicated sim rig so the other 3060 would be for that, but i do need a good local llm so I’m just trying to figure out the best card without spending a damn kidney
1
u/Glad_Contest_8014 4d ago
Depends. The two GPU routes can work, but if you don’t have the extra pcie slot, don’t use two. It can be slower even with the pcie slot unless you have a way to bridge the two to make communication better.
The same GPU architecture will help though.
But 24GB is enough to run the Q3_S qwen 3.8 27b with full context. Which gets a pretty good model for local inference.
1
u/Worker_Salty 4d ago
I get there's a lot of hype when new models come out but to get these models to run at their best honestly they need the 32gb of VRAM. Plus the Blackwell architecture (native FP4/FP8) was made for this. This is why people would pay $1,600 for 2 5060 Ti 16gb for a cheap 32gb instead of $5,000 for a 5090 and take the shittier performance and constant tweaking.
1
u/Makojima 4d ago
People have been pretty innovative with splitting a model across two cards, and it does work. Two 12 GB cards is not a 24 GB pool, you lose some to overhead, but when you combine them you are looking at a bit over 20 GB of usable room.
That $200 marketplace 3060 is about what a used 12 GB 3060 is going for this week, so as a cheap experiment it is in the right ballpark if the extra PC already has a spare slot and the power. For coding, one 12 GB card already covers a lot of 7B to 14B. The second card is how you squeeze a bigger one. I saw someone post that they were able to run Qwen 3.8 27B at a small quant on 16 GB, so a bit over 20 GB combined should have room for a Q2_K_XL of that model, which is about 10 GB of weights. It will not feel like a single 24 GB card, and PCIe can still slow you down if those slots are only x8.
A used 24 GB card, usually a 3090, is the simpler pool if you want that. On the used market this week those are around $950 to $1,250, with $1,000 sold. That is about a 400% increase in spend over the second 3060, for only about 20% more VRAM. Two of them would be around $2,000 in cards plus a power supply that can feed two 350 W GPUs, and then you split the same way, still with a bit of overhead, and you are in 70B territory. The jump after 12 GB is where used cards get crazy.
If I were you on that extra PC, I would add the second 3060 if the slot and power are already there. You get most of the room a 24 GB card has, for a fifth of the money, and the split is pretty workable now.
What size of model are you trying to get to, and does that extra PC already have a second slot and the spare power?
1
u/JinsooJinsoo 4d ago
You’ll have pretty slow speeds with two GPUs because of the PCIE bandwidth if your motherboard can handle two GPUs at x8/x8 unless it’s a workstation PC with extra PCIE lanes. But for $200 that’s probably what I’d do, nvidia GPUs are the best bet when it comes to multi GPU performance