ディスプレイアドバイザ
表示は無料、変更はPro
WindowServerが画面を描画するためにどれだけ働いているかを表示し、その一部を取り戻せる可能性のある変更を提案します。
The problem
If your Mac drives an external display, WindowServer, the macOS process that draws every window on every screen, can use a noticeable share of the CPU. You may see it near the top of Activity Monitor and have no idea what to do about it.
The causes are mostly settings. A scaled resolution makes macOS draw a bigger picture and shrink it to fit. A high refresh rate means more frames to draw. Each extra display adds its own picture. Hedroom reads what your displays are doing and tells you which of those applies on your Mac.
How it works
- Read. While the Display advisor is open, Hedroom reads WindowServer's CPU as a share of one core, at most every 5 seconds. If it cannot read it, it says "Unavailable" and shows no number, never a zero.
- Look at each display. Its resolution, its refresh rate, and whether macOS is drawing more pixels than the panel has and scaling them down.
- Tip only from data. Tips come from what it reads: a scaled mode, a refresh rate above 60 Hz on an external display, three or more displays, or Reduce Transparency. Each carries an impact such as "up to −N% CPU", a ceiling worked out from how many pixels per second would no longer be drawn. When it cannot estimate, it says "No estimate".
- Try it, with a safety net. Try it changes one display's mode. You have 15 seconds to press Keep or Undo. Do nothing and the old mode comes back.
- Measure. After Keep, Hedroom measures WindowServer for 5 minutes and writes a receipt. The change lasts until you log out.
What you will see
The screen shows WindowServer's live CPU with one sentence that follows the data ("WindowServer is light right now." when it is under 5%), then a card for each connected display. A scaled display shows the picture macOS draws as a dashed frame around the one you see, with an "Extra work" chip. Below are the tips, biggest first, each with its reason, an impact chip and a button: Try it, or Open Settings for Reduce Transparency, which Hedroom never flips for you. When there is nothing to change it says "Nothing to change."
After you press Try it, a sheet counts down from 15 seconds with Keep and Undo; Esc undoes. Once you keep a change, it says Hedroom is measuring for 5 minutes and that the change stays until you log out.
A worked example
Example, not real data
A scaled external monitor
Say you have a 4K external display set to "Looks like 2560×1440". macOS draws a 5120×2880 image, then shrinks it to fit the panel, so WindowServer does extra work. The advisor shows the dashed frame and a first tip: use the mode that draws exactly the panel's pixels, with its ceiling.
You press Try it. The display changes, you judge whether the result is comfortable to read, and press Keep. Five minutes later the receipt compares WindowServer before and after. If the drop is smaller than Hedroom can tell apart from normal ups and downs, it says "No measurable effect." and you can press Undo.
Details and limits
できること
- 画面を開いている間、WindowServerのCPUをコア1つに対する割合で読み取ります。読み取れない場合は「利用できません」と表示し、数値は表示しません。
- 各ディスプレイの解像度、リフレッシュレート、そしてmacOSが大きな画像を描画して縮小しているかどうかを表示します。
- ヒントは、読み取った内容だけに基づきます。パネルのピクセル数より多く描画する拡大縮小モード、外部ディスプレイでの60 Hz超のリフレッシュレート、3台以上のディスプレイ、そして「透明度を下げる」です。
- 「試す」は、1つのディスプレイのモードを変更します。「維持」または「取り消す」を押すまで15秒あり、何もしなければ元のモードに戻ります。
- 「維持」のあと、WindowServerを5分間測定し、レシートを作成します。
What it will not do
- 「試す」を押すまで何かを変更すること。
- 変更を永続させること。「維持」したあとも、ログアウトするまでしか保持されません。
- 「透明度を下げる」を代わりに切り替えること。そのヒントはシステム設定を開きます。
- 割合を約束すること。効果の数値は「最大」と表示され、予測ではなく上限です。
Limits
- 実際に小さな低下があっても、レシートでは「測定できる効果はありません」と表示されることがよくあります。これはレシートが慎重だということです。
- パネル本来の解像度より低いモードでは、文字がぼやけて見えることがあります。Hedroomはヒントでそのことを伝えます。
- 15秒の間にHedroomがクラッシュした場合、確定していないモードは、すぐにではなく、次回の起動時またはログアウト時に元に戻ります。
無料かProか
測定値とヒントは無料です。試すにはProが必要です。元に戻す操作は、ロックされることはありません。
Try it changes your display, which is why it, and only it, is Pro.
Questions people ask
Could it leave my screen in a bad state?
Every change has a 15-second Undo, and a change you do not confirm goes back by itself. Hedroom writes a small journal before changing the mode. If it crashes during the 15 seconds, the unconfirmed mode comes back at the next launch or when you log out, not at once.
Does it need any permission?
It asks for no admin password. It reads and changes display modes through the same system calls any app can use, and reads WindowServer's CPU with the system's own ps tool.
Does looking cost battery or CPU?
It reads WindowServer only while the screen is open, at most every 5 seconds, and every 10 seconds while a display-change receipt is measuring, about 6 to 16 minutes. Each read is one run of ps, which took about 20 milliseconds of CPU on the Mac it was checked on.
Will it change my displays by itself?
Never. A display change needs your click on Try it. No rule or schedule can do it.