本地 AI 内存余量
可免费查看，更改需要 Pro
在你下载或加载本地模型之前，先检查它能否放进你 Mac 的内存。
The problem
Downloading a local model is a long wait, and the failure comes at the end: it will not load, or it loads and your Mac starts swapping. The size on the download page is only part of the answer, because the context length you choose adds memory too.
Local AI headroom answers the question first. You pick the model size and context. Hedroom estimates what it needs, compares that with what your Mac can give a model right now, and names the line that decided the answer.
How it works
- Pick. Choose a model family and size, 4-, 8- or 16-bit, and a context from 4K to 128K. Hedroom names families and sizes only; it recommends no product.
- Estimate. It adds up the weights, the context cache (which grows with the context) and runtime overhead, each shown as "about". A 15% margin covers the fact that layer and head counts are typical for a family, not read from your file.
- Compare. The total is checked against the GPU memory limit and against what is free right now (free memory plus cached files; compressed memory does not count).
- Answer. Fits, Tight, Make room or Won't fit, with the line that decided it.
- Act, if you choose. Make room lists apps to relaunch or quit through the normal safety checks. On some Macs, Hedroom can raise the GPU limit until you restart, after a confirmation.
What you will see
A big verdict, "Fits.", "Tight.", "Fits, after making room." or "Won't fit.", with a sentence naming the line that decided it and the parts of the estimate: "Weights about … · context about … · runtime about … The estimate can be off by about 15%." A gauge shows what the model needs against two markers: what the GPU can use and what is free right now.
Beside it sits the GPU memory limit control, with a warning always on screen (less memory for macOS, your Mac can slow down or become unstable, it lasts until you restart), and a list of model apps Hedroom finds running: Ollama, LM Studio, Jan and GPT4All, with what they use. On a 16 GB Mac the limit control is off and says why.
A worked example
Example, not real data
A mid-size model on a 16 GB Mac
Say you want to try a Llama-family model at 8B parameters, 4-bit, with an 8K context. Hedroom estimates weights of about 4.8 GB, context of about 1.1 GB and runtime of about 0.8 GB: about 6.7 GB, or about 7.7 GB with the margin.
macOS lets the GPU use about two-thirds of a 16 GB Mac's memory by default, around 10.7 GB, so the GPU limit is not the problem. But say Chrome and Slack are open and free memory plus cached files reads about 7 GB. The low estimate fits and the high one does not, so the verdict is Tight, and the Make room list shows which apps hold the most. Hedroom promises no speed: it estimates memory only.
Details and limits
它做什么
- 你选择模型系列和大小、4、8 或 16 位，以及从 4K 到 128K 的上下文长度。
- 估算它所需的内存（权重、上下文缓存和运行时），然后与 GPU 可使用的内存以及现在的可用内存进行比较。
- 给出“放得下”“紧张”“腾出空间”或“放不下”的答案，并附上决定结果的那一行。
- “腾出空间”会建议通过 Hedroom 的常规操作，重新打开或退出占用内存的 App。
- 在 Ollama、LM Studio、Jan 和 GPT4All 运行时留意到它们，并说明它们占用多少。
- 可以在你确认之后，把 GPU 内存上限调高到你重新启动为止，确认中会说明留给 macOS 的内存有多少。
What it will not do
- 下载、加载或运行模型，或与模型 App 对话。
- 承诺速度。它只估算内存。
- 提供会让 macOS 剩下不到 8 GB 的上限。
- 未经你确认就调高上限。Hedroom 退出时会把上限恢复成原来的值，除非你期间自己改过。
Limits
- 估算可能有约 15% 的误差。层数和注意力头数是某个模型系列的典型值，不是从你的文件中读取的。
- macOS 没有公布它默认的 GPU 上限。Hedroom 显示的是它自己的判断：不超过 36 GB 的内存取三分之二，超过的部分取四分之三。
- 在内存为 8、16、18 或 24 GB 的 Mac 上，Hedroom 不提供更高的上限，因为它允许的最大值不会超过 macOS 已经给 GPU 的量。
- 调高上限需要与风扇控制相同的辅助工具，需要在“系统设置”中批准。更高的上限会给 macOS 留下更少的内存，如果内存不足，你的 Mac 可能会变慢或变得不稳定。该设置会保持到你重新启动为止。
免费还是 Pro
检查以及读取 GPU 内存上限是免费的。调高上限属于 Pro。重置永远不会被锁定。
Raising the limit changes how your Mac behaves, which is why it is Pro.
Questions people ask
Does Hedroom download or run the model?
No. It never downloads, loads or runs a model, and never talks to a model app. It estimates memory and notices which model apps are running.
How accurate is the estimate?
It can be off by about 15%. The weights come from a simple formula, and layer and head counts are typical for the family, not read from your file. The verdict checks both the estimate and the estimate plus margin, so a borderline case reads Tight rather than Fits.
Is raising the GPU memory limit safe?
It leaves less memory for macOS, and your Mac can slow down or become unstable if memory runs short. Hedroom never offers a limit that leaves macOS less than 8 GB, shows how little is left before you confirm, puts the limit back when it quits, and the setting goes away at restart anyway.
Does it need the helper?
Checking is free and needs no helper. Raising or resetting the limit uses the same helper as fan control, which requires approval in System Settings. Approving the helper has the steps.