Key takeaways
- Start from your memory: a graphics card's VRAM, an Apple silicon Mac's unified memory, or system RAM for CPU-only use, then compare a published figure for the exact file.
- Read what a figure covers: Google's Gemma 4 table counts only the weights, not the context window or supporting software, and a longer context needs more memory.
- Read the license for the exact release, then test speed and answers yourself; a model that fits can still run slowly, and USASI does not benchmark or rank models.
On this page
- Step 1: Find out which memory you have
- Step 2: Why memory sets the limit
- Step 3: What quantization trades
- Step 4: Read the published figure, and what it leaves out
- Step 5: Match a runtime to your hardware
- Step 6: Check the license before you use it
- Where the USASI finder and memory pages fit
- Fitting is not the same as running well
- Worked example: a desktop with an 8 GB graphics card
- What you can do next
What you can run depends first on memory: a graphics card's own memory (VRAM) on a PC, the unified memory that the processor (CPU) and graphics processor (GPU) share on an Apple silicon Mac, or system RAM if the CPU does the work alone. Find a published memory figure for the exact file you would download, including its quantization (how many bits store each weight), and note what the figure leaves out, such as the context window. Check that your runtime, the app that loads the model, supports your hardware, and read the license before you rely on the model. A model that fits can still run slowly. Speed and quality vary with hardware, settings, and task, and USASI does not benchmark, test, or rank models. This page is general information.
Step 1: Find out which memory you have
- A PC with a graphics card. The vendor's specification page lists the card's memory, and one product name can come in two sizes: NVIDIA's RTX 5060 family page (external site: nvidia.com) lists the RTX 5060 Ti with "16 GB / 8 GB GDDR7." For Windows 10, Microsoft says Task Manager's Performance pane shows dedicated GPU memory, and notes that some GPUs do not use dedicated GPU memory, in which case the Dedicated GPU memory counter is not available or reads 0 (Microsoft Learn (external site: learn.microsoft.com)).
- An Apple silicon Mac. The README (external site: github.com) for Apple's MLX framework says arrays "live in shared memory" and can be used on the CPU or GPU without transferring data. Apple's MacBook Air specifications (external site: apple.com) list memory as a configuration choice: 16GB of unified memory, configurable to 24GB or 32GB. In Activity Monitor (external site: support.apple.com), the Memory tab shows "Physical Memory," the amount of RAM installed.
- CPU only. llama.cpp's README (external site: github.com) lists CPU support, including AVX, AVX2, AVX512, and AMX on x86 processors and optimizations for Apple silicon. Ollama's macOS page (external site: docs.ollama.com) lists Apple M-series Macs with "CPU and GPU support" and x86 Macs as "CPU only."
Step 2: Why memory sets the limit
The model's weights have to fit, plus working memory that grows with the conversation. Ollama's context length page (external site: docs.ollama.com) says "Setting a larger context length will increase the amount of memory required to run a model." Its default context depends on VRAM: 4k tokens below 24 GiB, 32k from 24 to 48 GiB, and 256k at 48 GiB or more. Its FAQ (external site: docs.ollama.com) says required RAM scales with the number of parallel requests times the context length.
When a model does not fit on the GPU, runtimes can split it: llama.cpp offers "CPU+GPU hybrid inference to partially accelerate models larger than the total VRAM capacity," and Ollama's ollama ps command shows where a model loaded: "100% GPU," "100% CPU," or a split such as "48%/52% CPU/GPU." Splitting costs speed. OpenAI's guide to running gpt-oss with Ollama (external site: developers.openai.com) says you can offload to the CPU when short on VRAM, "but expect it to run slower," and Ollama advises avoiding CPU offload for best performance.
Step 3: What quantization trades
LM Studio's download guide (external site: lmstudio.ai) calls the Q options for a model "copies of the same model, provided in varying degrees of fidelity": quantization compresses the files "while giving up some degree of quality." It suggests "a 4-bit option or higher if your machine is capable enough for running it." llama.cpp's quantize README (external site: github.com) gives sizes for Meta's Llama 3.1 8B: 14.96 GiB at 16 bits (F16), 7.95 GiB for Q8_0, and 4.58 GiB for Q4_K_M. It says quantization "may introduce some accuracy loss," and warns that requantizing an already quantized file can severely reduce quality compared with starting from 16 or 32 bits. Quantization explains the formats.
Step 4: Read the published figure, and what it leaves out
A figure is only as useful as its assumptions. Google's Gemma 4 overview (external site: ai.google.dev) (last updated July 8, 2026) gives the approximate GPU or TPU memory needed to load each model, including a "20% overhead of loading additional things." For Gemma 4 12B, it lists 26.7 GB at BF16 (16-bit), 13.4 GB at SFP8 (8-bit), and 6.7 GB at Q4_0 (4-bit). The page says these estimates "only account for the memory required to load the static model weights," without the VRAM needed for supporting software or the context window. Memory use grows with the total number of tokens in your prompt and the response, it adds, and the numbers may change with your inference tool and environment.
Other figures are framed differently:
- "Runs within." The gpt-oss-20b card (external site: huggingface.co) says MXFP4 quantization of its mixture-of-experts weights lets gpt-oss-20b "run within 16GB of memory." OpenAI's Ollama guide says the model is best with at least 16GB of VRAM or unified memory.
- Listed size. Ollama's library page (external site: ollama.com) lists
gpt-oss:20bat 14GB, under "Size / Usage," with a 128K context window. That is the model's size, not the memory needed once a long context is in use.
Step 5: Match a runtime to your hardware
Runtime requirements change, so check the current page:
- Ollama. macOS Sonoma (14) or newer (macOS (external site: docs.ollama.com)); Windows 10 22H2 or newer, with NVIDIA driver 551.61 or newer for NVIDIA cards (Windows (external site: docs.ollama.com)). Its hardware support page (external site: docs.ollama.com) lists NVIDIA GPUs with compute capability 5.0 or higher, AMD GPUs through ROCm v7, Apple GPUs through Metal, and Vulkan. Its install pages say models "can be tens to hundreds of GB in size."
- LM Studio. Its system requirements (external site: lmstudio.ai) list Apple silicon (M1 to M4) with macOS 14.0 or newer and "16GB+ RAM recommended," adding that 8GB Macs may work with "smaller models and modest context sizes"; Intel-based Macs are not supported. On Windows, x64 processors need AVX2, with at least 16GB of RAM and 4GB of dedicated VRAM recommended. Its terms of service (external site: lmstudio.ai) name the provider as Element Labs, Inc.
- llama.cpp. Its README lists backends including CUDA (NVIDIA), HIP (AMD), Metal (Apple silicon), Vulkan, and SYCL (Intel GPUs), alongside CPU support.
- MLX. Its README calls MLX an array framework for machine learning on Apple silicon. Its text-generation package, mlx-lm (external site: github.com), says models large relative to the machine's total RAM "can be slow."
Hugging Face's GGUF documentation (external site: huggingface.co) describes GGUF as a file format that "is designed for use with GGML and other executors," and lists llama.cpp, LM Studio, GPT4All, and Ollama under usage with open-source tools.
Step 6: Check the license before you use it
Read the license for the exact release you download, whoever made the copy. Three examples:
- gpt-oss-20b: Apache 2.0, according to its card (external site: huggingface.co).
- Gemma 4 12B: the instruction-tuned card (external site: huggingface.co) lists Apache 2.0 and links to Google's license page (external site: ai.google.dev), which reproduces the Apache License 2.0.
- Llama 3.1 8B: the Llama 3.1 Community License (external site: github.com), a custom license. It requires "Built with Llama" to be displayed when you distribute the model or a product containing it, requires a distributed model built with it to have a name beginning with "Llama," brings in an acceptable use policy, and sets a separate process for licensees above 700 million monthly active users.
For a quantized copy uploaded by someone else, Hugging Face's model card documentation (external site: huggingface.co) says the base_model field can name the original, with the relationship marked "quantized"; follow it back to the original license. A gated download (external site: huggingface.co) asks you to share your username and email address with the authors. USASI's license guide summarizes common licenses.
Where the USASI finder and memory pages fit
- The finder checks a small set of documented configurations against what you enter, explains why each matches or not, and shows what is unverified. "Estimated to fit" means a publisher's stated figure for one exact variant is within the amount you entered, not that USASI ran it. Where no figure is published, the result says the evidence is insufficient.
- Local AI by memory applies the same rule to fixed amounts: 8, 12, 16, and 24 GB of VRAM, and 8, 16, 24, 32, and 64 GB of Apple silicon unified memory. The VRAM pages compare only publishers' graphics-memory figures; the Apple silicon pages compare unified memory with graphics-memory and system-memory figures alike.
- The model size calculator shows the storage arithmetic for weights at 32, 16, 8, or 4 bits each, and what it leaves out.
- USASI does not benchmark or rank models, and no record or finder entry claims a hands-on test (review levels).
Fitting is not the same as running well
Speed depends on more than memory. llama.cpp's performance troubleshooting notes (external site: github.com) show one 4-bit, 30-billion-parameter model on one machine generating anywhere from under 0.1 to 9.1 tokens per second, depending only on its thread-count and GPU-offload settings. Quality depends on the model, the quantized file, and your task. Test with your own prompts, and record the runtime version, the exact file, the context length, where the model loaded, and the date.
Worked example: a desktop with an 8 GB graphics card
Jo is a fictional reader invented for this page, and the choices are Jo's, not a recommendation. Task Manager shows Jo's Windows desktop with 8 GB of dedicated GPU memory and 32 GB of system RAM; Jo wants a local model for drafting and summarizing. Steps are labeled Stated (by a publisher), Estimated (Jo's reasoning), or Tested (what Jo measures). Checked October 13, 2026; USASI did not run either model.
- First candidate (Stated). OpenAI's Ollama guide says gpt-oss-20b is best with at least 16GB of VRAM or unified memory. Jo has 8 GB.
- Estimated. It would probably be split between GPU and system memory, which the same guide says runs slower.
- Second candidate (Stated). Google's table lists 6.7 GB to load Gemma 4 12B at Q4_0, weights only. Google's Hugging Face repository (external site: huggingface.co) offers a Q4_0 GGUF of the instruction-tuned model, made with quantization-aware training: a 6,975,879,296-byte file (about 7.0 GB), plus a smaller mmproj file.
- Estimated. That leaves little of the 8 GB for the context window and other software, so Jo plans a short context, expects part of the model may run on the CPU, and notes Gemma 4 E4B (4.5 GB at Q4_0 in the same table) as a fallback.
- License (Stated). The repository's card lists Apache 2.0.
- Runtime (Stated). LM Studio on Windows needs AVX2 on x64 processors, so Jo confirms the processor has it.
- Tested. Jo runs ten typical prompts and writes down the LM Studio version, the context length, how long answers take, whether they are usable, and the date.
Jo's outcome: start with Gemma 4 12B at Q4_0 and a short context, and switch to the smaller model if answers are too slow. Another model whose published figure fits could serve as well.
What you can do next
- Read understanding inference hardware, quantization, and choosing hosted access or local inference.
- Open the finder or a memory page, such as 8 GB of VRAM or a 16 GB Apple silicon Mac.
- Browse local runtimes in the catalog: Ollama, llama.cpp, and MLX.
- Visit the local AI hub and the license guide.
- Look up quantization, GGUF, context window, and GPU in the glossary.
- Before trusting any "runs on a laptop" claim, see how to check an AI claim.
Sources
All read on October 13, 2026.
- llama.cpp (ggml-org): README (external site: github.com); quantize README (external site: github.com); Token generation performance troubleshooting (external site: github.com)
- Ollama: Hardware support (external site: docs.ollama.com), Context length (external site: docs.ollama.com), FAQ (external site: docs.ollama.com), macOS (external site: docs.ollama.com), Windows (external site: docs.ollama.com), gpt-oss library page (external site: ollama.com)
- LM Studio (Element Labs, Inc.): System requirements (external site: lmstudio.ai); Download an LLM (external site: lmstudio.ai); App Terms of Service (external site: lmstudio.ai) (version August 23, 2026)
- Apple: MLX README (external site: github.com); mlx-lm README (external site: github.com); MacBook Air technical specifications (external site: apple.com); View memory usage in Activity Monitor on Mac (external site: support.apple.com)
- Google: Gemma 4 model overview (external site: ai.google.dev) (last updated July 8, 2026); gemma-4-12B-it card (external site: huggingface.co) (revision 707f0a3); gemma-4-12B-it-qat-q4_0-gguf repository (external site: huggingface.co) (revision 29d0977) and its file listing (external site: huggingface.co); Gemma 4 license (external site: ai.google.dev)
- OpenAI: gpt-oss-20b card (external site: huggingface.co) (revision 6cee5e8); How to run gpt-oss locally with Ollama (external site: developers.openai.com)
- Meta: Llama 3.1 Community License Agreement (external site: github.com) (version release date July 23, 2024)
- NVIDIA: GeForce RTX 5060 family (external site: nvidia.com)
- Microsoft Learn: GPU Process Memory counters report incorrect value (external site: learn.microsoft.com)
- Hugging Face documentation: GGUF (external site: huggingface.co), Model Cards (external site: huggingface.co), Gated models (external site: huggingface.co)