Ask HN: MacBook vs. Dedicated GPU for LLM

[mzubairtahir]

For those who are using llms on macbook, Want to understand how macbook is different than dedicated GPU in running those models? and how to know how much a macbook is capable of running a model?

[cylentwolf]

I asked a few of my friends that are ML engineers this question and all of them said to run the LLMs in the cloud with their infrastructure because it was going to be way faster. If you just want to tinker around I would look at @JSR_FDD's comment.

[throwawaytea]

Next you're going to tell me that car salesman recommend just leasing new cars, doctors recommend just following the standard of care, construction workers just recommend subbing it out, and your tech friends say just use AWS.

[ramraj07]

If your car salesman friend gives you stupid advice it either means he is stupid or he is not your friend.

[throwawaytea]

I sold cars for a decade and wouldn't even take the insanely cheap priced company demo car, just driving my 10 year old car instead.

On that note though, most car salesman are somewhat stupid, although the best ones are atleast normal. (I was a cal mechE grad and top 0.2% nationwide car salesman). They also slowly brainwash themselves into believing most of what they say.

[derwiki]

There are more factors than speed though, like: privacy

[jpgvm]

If you want a massive MacBook anyway then it's great. They are decent for local LLMs, awesome for local image models and it's a MacBook so AppleCare+ has your back. IMO it's a no brainer if you wanted a MacBook anyway but it's a poor choice if your reason to buy it is to run LLMs.

[zepearl]

I agree. To run an acceptable model (e.g. Qwen/Qwen3.6-27B or google/gemma-4-31B) with a good quantization (minimum Q5) with a good context size (min 64k) you could buy 2 or even 3 GTX 5060 16GiB VRAM for ~550$ each. Fyi the much faster MoE models were useless for my usecases - e.g not able to correctly identify me/I/you, endless thinking loops, etc.

I'm currently running those models using an RTX 5070 12GiB + RTX 5060 16GiB + RTX 3060 12GiB with a 96k context size with MTP/speculative decoding and I'm quite happy (the 5070 is about 4x faster than the 3060, the 5060 is inbetween them so about 2x faster than a 3060).

[eklavya]

How are you running these together, splitting the model somehow or did you mean different models on any one card at a time?

[nubg]

how many tokens per second do you get?

[cybertim]

I bought two RTX3080s with 20GB during my holiday in china (set me back 700euros) I'm getting 800-1000 input tps and 60-100tps output with Qwen 3.6 27b Q8 (MTP, P2P, 200k context) this feels like opus4.5 level while coding (pi harness). Also easy to just host your own openai compatible api from home this way and still use your MacBook as dev station.

[mzubairtahir]

are you saying because of speed or it just cant run them?

[JSR_FDED]

MacBooks with their unified memory behave like a slow GPU with enormous amount of video RAM. So you can run large smart models slowly.

Dedicated GPUs have less video RAM so can run smaller less smart models quickly.

[EagnaIonat]

> MacBooks with their unified memory behave like a slow GPU with enormous amount of video RAM. So you can run large smart models slowly.

With the model using MLX the speed increase is night and day. Even non-MLX is good.

You also don't have the transfer costs related to moving CPU data into the GPU.

[visarga]

Macbook M5 64GB - can run gemma-4-26b-a4b-it-4bit and Qwen3.6-35B-A3B-4bit at about 1500 tps prefix and 45 tps decode on contexts up to 100K tokens using MLX. It's faster than Claude. I was really surprised, chat quality is also similar to Claude for gemma4. Agentic works but does not compare to cloud models, you can still make agents where top level is code.

[mzubairtahir]

sorry but asking again: how much memory is actually useable by gpu in macbook? as it is shared(os and apps also have to use same memory)? and it is different than dedicated gpu memory?

[gizajob]

It’s completely shared so the OS and everything else takes up maybe 8GB of the RAM. On a 64GB machine you can run models about 45GB in size and still have space for those models run other tasks which themselves might need ram. To a user, the GPU appears to just use the RAM as much as it needs same as any other process running on the system. You can see what space your LLMs are taking up in Activity Monitor (or htop) and how much GPU capacity they’re using (all of it)

[cco]

Rule of thumb is about 70-80%.

[j45]

You can adjust the percentage available both on the MacOS side and how much the model uses.

[exabrial]

Do Mac Pros provide more headroom? noob here, noob questions

[rho138]

Idk why you’re being downvoted for asking a question. Pending specs they _could_ provide more headroom for a larger model but they would still be limited by the CPU and it’s associated bus speeds.

[JSR_FDED]

In what sense? Headroom for what?

[mzubairtahir]

how much memory is actually useable by gpu in macbook? as it is shared?

[pylotlight]

roughly ~50–56GB, although this is somewhat configurable with iogpu.wired_limit_mb. By default, macOS reserves ~25% of memory for the system.

[nichch]

My opinion is that you should wait for 6-12 months before making a purchase either way.

Open weight models are getting good. With GLM 5.2 now chasing Opus, I'm very excited to see a smaller model's distillation.

Plus, the OLED MacBook Pro should be released by then.

[speedgoose]

The OLED touchscreen MacBook is rumoured to be called MacBook Ultra now, and it has been delayed quite a few times. I will probably cost the same than a decent bike.

[gizajob]

MacBook Ultra Expensive (when equipped with 256 or 512 Gb of ram)

[Frannky]

This is my opinion too. Even if you buy hardware like a cluster of 8xGB10s or 4 A100s, they'll still be slow and a little dumber than what you're used to. We need to wait a little for better hardware. Lots of companies are pushing the frontier, so hopefully it'll come very soon.

Competition and innovation will hopefully make the bubble pop, and we'll get reasonably priced local hardware to run very intelligent models. Something like Talaas with GLM 5.2 would be pretty cool. Or Apple printing the latest model onto hardware—it would give a new reason to buy a new Mac every year (a new ai model with every new version).

[gizajob]

The hardware is here today for people prepared to tolerate mild amounts of latency. It’s easy to forget that computing tasks used to often take major amounts of time - rendering an audio file, rendering a video, transcoding – all kinds of tasks took minutes or even hours of the computer spinning its fans on maximum just to deliver the result. AI and agentic AI and diffusion is the next round of that - trading a small bit of your waiting time for phenomenal power. The datacentre builders trying to get you hooked on instant responses on the LLM platforms have made you think that a “good” AI responds instantly and completely interactively - they can still be brilliant with a bit of delay. And having a competent agent doing things on my local machine, it doesn’t really matter if it takes ten minutes or an hour or six hours to complete a task while I’m out doing other things.

[Frannky]

Hmm, I have access to A100s and a GB10, but if I use the models hosted there to code, I waste a lot of time waiting for answers and correcting errors. The amount of work I get done thanks to the quality and speed of frontier hosted models let me be insanely productive and have a lot of free time. I could use the slow local setup, but at what price?

[gizajob]

Well if all that was taken away from you and you had to go to the bank to ask for the money to rebuild so you could become as productive as you are now, what would that cost and would the bank loan you the money?

[FireBeyond]

The racks we're deploying are effectively GB300 NVL72s: 72 Blackwell Ultra GPUs 36 Grace CPUs, 20.7TB of unified HBM3e.

Works out to about 1.1exaflops of fp4. Networking is 800gbps.

120kW per rack.

[gizajob]

That’s a majorly impressive computer. What’s the price of that per rack? Deploying for what?

[FireBeyond]

$3-4M per rack. A variety of workloads...

[dust42]

With a M5 16c 48GB and Qwen 3.6 35B Q4 I get up to 1900 PP/s and 80 TG/s. With an Nvidia 5090 I get 7800 PP/s and 280 TG/s.

Together with pi mono I wouldn't want to go back to Claude & Co. Speed, quality of the answers, short answer times at any time of day - once you have eaten from the fruit your definition of SOTA will change...

For reference, I do software development since 30 years, I am not vibe coding the umpteenth todo list.

[tosh]

macbooks (macs in general) are a good package for llms because they come with so much RAM

and for llms more RAM means access to better models

macbooks might not be as fast as a GPU with similar amount of RAM but more affordable and well integrated

last but not least: compared to a PC+GPU the macbook is either silent (air) or at least way less annoying when you care about noise

for ultimate flexibility and low noise: GPU in the cloud for when you need/want it is probably also most cost effective if you don't have workloads that need to run 24/7

[EagnaIonat]

With a dedicated GPU, the lag is in transferring data to the GPU. You don't have that lag in ARM.

But it really depends on what it is you want to do. An MLX optimised recent model will run fine and at decent speeds. Granite4.1 (a few months old) for example takes up 2GB of memory, insanely fast and results are good vs much bigger models like gpt-oss-120b (a year old). It even runs on an M1 mac with good speeds.

The models are only getting better.

[epsteingpt]

Both are going to be super super slow and low payback.

You gotta really want it right now.

It's still early!

[g-technology]

Around February or march I started looking into hardware options to help me start learning about training models and working with them. My budget was limited and an apple refurbished 32 gb Mac mini was far and away the best option for my budget. I wish it was faster but I can let it run 24/7 with no noise and minimal power draw. I just arrange long running tasks for when am asleep or at work. Then as a huge plus I have an awesome daily driver machine for whatever else I want to do

[alecco]

MacBooks have lots of RAM and no PCIe bottleneck, but ~10x fewer FLOP/s than a much cheaper Nvidia GPU. Test LLMs on rented GPUs on vast.ai or other similar services (beware storage etc). Don't spend thousands before trying and knowing exactly what you get.

Also beware local models tend to be slow. Also, the main optimization trick for LLM inference is running large batches (concurrent users) and you won't take advantage of this (batch=1).

IMHO using Macs for LLMs is a fad. An expensive fad.

[browningstreet]

It’s kind of amazing how steadily this question is asked in every forum where it can be asked. Kind of amazing that the answers previously given can’t reach the next person who’s going to ask it.

[throwawaytea]

What's crazy is these people want to invest decent money to use AI/LLMs, but somehow don't think to just ask an AI chat bot which would easily answer it for them and any follow-up questions.

[derwiki]

Isn’t it all rapidly evolving? I guess beyond that it’s a signal of growing interest in local LLMs

[brcmthrowaway]

Dual 3090 >>> Any Apple product.

[kylec]

Doesn't the 3090 cap out at 24GB VRAM? That's not a lot to run a local model

[brcmthrowaway]

https://old.reddit.com/r/LocalLLM/comments/1ug428c/4x3090_19...

[mzubairtahir]

but still it can run handsome models

[EagnaIonat]

Latest MBP goes up to 128GB of memory.

[gnabgib]

> Dual 3090 >>> Any Apple product.

Dual 3090s are terrible airpods

[tim-tday]

I snorted

[gizajob]

Local LLMs running in LM Studio on a MacBook Pro work great, if you’re prepared to wait for the answers because using an LLM locally is much much slower than having the instant results appear when using an online LLM like ChatGPT or Claude. You can also run OpenClaw on the MacBook and have that act as the front end for the LLM, to get full interactivity and have it install command line tools on your Mac to perform whatever tasks you’ve set it.

If you don’t already have a MacBook, then there’s a bit of a sweet-spot for the AI experimenter right now, which is to buy a second-hand 16” MBP with an M1 Max chip and 64GB of shared ram. Because these are about 5 years old now, they have depreciated to the point where they can be had for around £1100 / €1300 / $1500 and make a phenomenal platform for learning because the 64Gb of shared memory means you can host models up to about 48GB in size, and then task them to do interesting things with coding without ever having to worry about token burn.

The downside is that they’re slow, and prone to having to be nudged to keep them on track, but that’s part of the fun too. The “latency” is atrocious granted - you ask something and the machine thinks for a few minutes before saying anything which is a different experience to using Claude. But… it does work. You can think of yourself more like a manager with a junior member of staff and set the machine running and leave it to do its thing for a couple of hours which can be actually useful work, but this approach will likely be shouted down by some commenters here who treat Claude like some kind of expensive and quick-fire dopamine pump. Can also use a Mac like this for running diffusion models for image generation and suchlike in ComfyUI, even though, again, results will be slow. Spending more money on a more recent MBP with as much RAM as you can afford will deliver the same results more expensively in a quicker and quicker time.

To get the same kind of size of model you’d have to combine a couple of Nvidia 3090 24GB cards in a decent workstation with the PCI capacity to handle them, or hack some kind of solution to hang GPUs off the back of a motherboard on ribbon cables with the GPUs running on their own PSU, which is what I’m building next… the difference is those cards have 24GB of vram and cost about $1000 each second-hand, but will operate much much faster than the M1 Max MBP, or even the most recent M5 because they have so much more bandwidth (because they’re burning 350 watts on GPU compute rather than 140 watts total which is what a super efficient MBP has for the cpu/gpu/screen/everything).

So say you had $6000 to spend today, you could buy a second hand workstation and craft a solution with external GPUs which would completely smoke any Mac in existence, even though macs have the edge in the size of model you’d can run (slowly) due to their shared memory. External GPUs and access to the Nvidia frameworks and general CUDA ecosystem wins out on the performance front though. A real sweet spot is to buy an M1 Max MBP and have that as your front end to a Linux workstation full of GPUs.

But any apple silicon MBP is a totally competent gateway drug to local agentic computing.

Google Gemini could give you an in-depth and useful discussion about this exact question.