Display-Berater
Kostenlos ansehen, mit Pro ändern
Zeigt, wie stark WindowServer beim Zeichnen Ihrer Bildschirme arbeitet, und bietet Änderungen an, die einen Teil davon zurückgeben können.
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
Was es tut
- Liest die CPU von WindowServer als Anteil eines Kerns, solange der Bildschirm geöffnet ist. Kann es sie nicht lesen, sagt es „Nicht verfügbar“ und zeigt keine Zahl.
- Zeigt Auflösung und Bildwiederholrate jedes Displays und ob macOS ein größeres Bild zeichnet und verkleinert.
- Gibt nur Tipps aus dem, was es liest: ein skalierter Modus, der mehr Pixel zeichnet, als das Panel hat, eine Bildwiederholrate über 60 Hz an einem externen Display, drei oder mehr Displays und „Transparenz reduzieren“.
- „Ausprobieren“ ändert den Modus eines Displays. Sie haben 15 Sekunden, um „Beibehalten“ oder „Widerrufen“ zu drücken; tun Sie nichts, kommt der alte Modus zurück.
- Nach „Beibehalten“ misst es WindowServer 5 Minuten lang und schreibt einen Beleg.
What it will not do
- Etwas ändern, bevor Sie „Ausprobieren“ drücken.
- Eine Änderung dauerhaft machen. Auch nach „Beibehalten“ gilt sie nur bis zur Abmeldung.
- „Transparenz reduzieren“ für Sie umschalten. Dieser Tipp öffnet die Systemeinstellungen.
- Einen Prozentwert versprechen. Wirkungsangaben sagen „bis zu“ und sind Obergrenzen, keine Prognosen.
Limits
- Kleine echte Rückgänge erscheinen im Beleg oft als „Keine messbare Wirkung“. Das ist der Beleg, der vorsichtig ist.
- Ein Modus unter der eigenen Auflösung des Panels kann Text unscharf wirken lassen. Hedroom sagt das beim Tipp.
- Stürzt Hedroom während der 15 Sekunden ab, kommt der unbestätigte Modus beim nächsten Start oder bei der Abmeldung zurück, nicht sofort.
Kostenlos oder Pro
Die Messung und die Tipps sind kostenlos. Ausprobieren gehört zu Pro. Widerrufen ist nie gesperrt.
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.