ローカルAIの余裕
表示は無料、変更はPro
ローカルモデルがMacのメモリに収まるかどうかを、ダウンロードや読み込みの前に確認できます。
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
できること
- モデルの系列とサイズ、4・8・16ビット、4Kから128Kまでのコンテキスト長を選びます。
- 必要な量（重み、コンテキストキャッシュ、ランタイム）を見積もり、GPUが使える量と現在の空きと比較します。
- 「収まります」「余裕なし」「空きを作る」「収まりません」のいずれかを、判断の決め手になった行とともに表示します。
- 「空きを作る」では、メモリを使っているアプリを、通常のHedroomの操作で再度開く、または終了することを提案します。
- Ollama、LM Studio、Jan、GPT4Allが実行中であることを検出し、それらが使っている量を表示します。
- macOSに残る量がどれだけ少なくなるかを示す確認のあと、再起動するまでGPUメモリ上限を引き上げられます。
What it will not do
- モデルをダウンロード・読み込み・実行すること、またはモデルアプリと通信すること。
- 速度を約束すること。見積もるのはメモリだけです。
- macOSに8 GB未満しか残らない上限を提案すること。
- あなたの確認なしに上限を引き上げること。Hedroomは終了時に、ご自身で変更した場合を除き、上限を元の値に戻します。
Limits
- 見積もりには約15%の誤差が出ることがあります。レイヤー数やヘッド数は、お使いのファイルから読み取った値ではなく、そのモデル系列の一般的な値です。
- macOSはGPUの初期上限を公開していません。Hedroomは独自の解釈を表示します。36 GBまではメモリの約3分の2、それを超える分は4分の3です。
- メモリが8、16、18、24 GBのMacでは、Hedroomはより高い上限を提案しません。許可できる最大値が、macOSがすでにGPUに割り当てている量を超えないためです。
- 上限の引き上げには、ファン制御と同じヘルパーが必要で、システム設定での承認が必要です。上限を高くすると、macOSに残るメモリが減り、メモリが足りなくなるとMacが遅くなったり不安定になったりすることがあります。この設定は再起動するまで続きます。
無料かProか
確認とGPUメモリ上限の読み取りは無料です。上限の引き上げはProの機能です。リセットがロックされることはありません。
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.