Beeldschermadvies
Gratis te bekijken, Pro om te wijzigen
Toont hoe hard WindowServer werkt om je schermen te tekenen en biedt wijzigingen aan die een deel daarvan kunnen teruggeven.
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
Wat het doet
- Leest de CPU van WindowServer, als aandeel van één kern, zolang het scherm open is. Als het die niet kan lezen, zegt het "Niet beschikbaar" en toont geen getal.
- Toont de resolutie en verversingsfrequentie van elk beeldscherm en of macOS een groter beeld tekent en verkleint.
- Geeft alleen tips op basis van wat het leest: een geschaalde modus die meer pixels tekent dan het paneel heeft, een verversingsfrequentie boven 60 Hz op een extern beeldscherm, drie of meer beeldschermen en Verminder transparantie.
- Probeer het wijzigt de modus van één beeldscherm. Je hebt 15 seconden om op Behoud of Maak ongedaan te drukken; als je niets doet, komt de oude modus terug.
- Na Behoud meet het WindowServer 5 minuten en schrijft een bon.
What it will not do
- Iets wijzigen totdat je op Probeer het drukt.
- Een wijziging permanent maken. Zelfs na Behoud geldt die alleen tot je uitlogt.
- Verminder transparantie voor je omzetten. Die tip opent Systeeminstellingen.
- Een percentage beloven. Effectcijfers zeggen "tot" en zijn plafonds, geen voorspellingen.
Limits
- Kleine echte dalingen worden op de bon vaak gelezen als "Geen meetbaar effect". Dat is de bon die voorzichtig is.
- Een modus onder de eigen resolutie van het paneel kan tekst zacht laten lijken. Hedroom zegt dat bij de tip.
- Als Hedroom crasht tijdens de 15 seconden, komt de niet-bevestigde modus terug bij de volgende start of wanneer je uitlogt, niet meteen.
Gratis of Pro
De meting en de tips zijn gratis. Probeer het is onderdeel van Pro. Ongedaan maken is nooit vergrendeld.
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.