Why AI Models Need a GPU: A Beginner Explainer (October 2026)
A plain-language walk through parallelism, matrix multiplication, VRAM, memory bandwidth, and why a CPU can run an LLM but rarely fast enough.
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A plain-language walk through parallelism, matrix multiplication, VRAM, memory bandwidth, and why a CPU can run an LLM but rarely fast enough.
Microsoft's first laptop on Nvidia's RTX Spark has a price and ship date. Here is what fits in 128GB of unified memory - and what it costs you.
Run an LLM against your novel without sending an unpublished manuscript to a vendor. Models, front ends, and what the tradeoffs are.
v0.40.0-rc0 ships MLX-by-default on Apple Silicon, v0.35 adds decision models, transformers runs llama.cpp quants. What changed and how to upgrade.
What the 'A3B' and 'A22B' suffixes mean, when Mixture-of-Experts beats a dense model on your hardware, and how to read a model card to tell which is which.
Local LLMs ranked by maximum context length: 32K, 128K, 256K, and 1M+ tiers, with the model that fits each tier and the VRAM each one needs.
Reasoning tokens, latency, and KV cache cost of thinking mode in local LLMs. How to toggle it per runner and when it is the wrong choice.
How Ollama, LM Studio, llama.cpp, and vLLM differ on model format, OpenAI-compatible API, hardware support, and which to pick for a home server.
Auth, reverse proxy, HTTPS, concurrency and audit: how a small team shares one local model without exposing it to the public internet.
Multi-GPU options for self-hosted AI when one card runs out of room: how Ollama, llama.cpp and vLLM split models, and what the interconnects actually cost.
Raspberry Pi 4 and Pi 5 can run small open-weight models on CPU alone. What fits on 2 GB, 4 GB, 8 GB, or 16 GB of RAM, and what speed is realistic.
The RTX 30 and 40 series cards that still clear current Ollama and llama.cpp floors, what VRAM tier each opens, and which variants are worth the used premium.
Practical patterns for letting two to six people in one home share one local model on one machine, with the right chat UI, bind address, and overlay network.
How much quality a smaller quant actually loses. Real MMLU and KL Divergence numbers across Q2_K through Q8_0, plus how to measure on your own workload.
What works on AMD Radeon and Intel Arc hardware today, where the official ROCm and SYCL paths stop, and how Vulkan fills the gap.
AMD's ROCm support splits by card and by OS, Intel archived both of its own LLM libraries this year, and llama.cpp is the path still standing.
8-bit measures close to lossless. 4-bit ranges from a 0.6% gain to a 59% drop on one benchmark, depending on the model. The figures, fully attributed.
Which open models run on CPU and RAM alone, how to size them, why mixture-of-experts helps, and what a machine with no discrete GPU cannot do.
Ollama, LM Studio, Jan, llama.cpp and vLLM compared: licences, engines, OpenAI-compatible APIs, multi-user serving, and which to install first.
Find your VRAM tier, then the current open-weight pick for chat, coding, vision, speech, translation or agents. Eighteen guides, one index.
Apple caps its on-device model at 4096 tokens per session, and Google's own tables put Gemma 4 E2B at 25.0 decode tokens/sec on an iPhone 17 Pro CPU.
Apple Silicon has no discrete VRAM, so tier guides mislead Mac owners. The real ceilings are bandwidth and the GPU-usable slice of unified memory.
Quantization formats compared with real file sizes and bits per weight. Why Q4 does not halve a model, and why low quants generate faster.
Two back-to-back merges add MiniMax Sparse Attention and a Qwen2.5-VL style vision tower to llama.cpp, but every existing MiniMax-M3 GGUF must be regenerated.