显示器建议
可免费查看，更改需要 Pro
显示 WindowServer 为绘制你的屏幕有多吃力，并提供可能让它减轻一些负担的更改。
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
它做什么
- 在屏幕打开时，读取 WindowServer 的 CPU，以占一个核心的比例表示。如果无法读取，它会显示“不可用”，并且不显示数字。
- 显示每台显示器的分辨率、刷新率，以及 macOS 是否正在绘制更大的图像再把它缩小。
- 只根据它读到的内容给出建议：绘制的像素比面板实际像素更多的缩放模式、外接显示器上高于 60 Hz 的刷新率、三台或更多显示器，以及“降低透明度”。
- “试一试”会更改一台显示器的模式。你有 15 秒时间点按“保留”或“撤销”；如果你什么都不做，旧模式会恢复。
- 点按“保留”之后，测量 WindowServer 5 分钟并写出回执。
What it will not do
- 在你点按“试一试”之前更改任何内容。
- 让更改永久生效。即使点按“保留”之后，它也只保持到你退出登录为止。
- 替你切换“降低透明度”。那条建议会打开“系统设置”。
- 承诺某个百分比。影响数字会写“最多”，它们是上限，不是预测。
Limits
- 很小的真实降幅，在回执上常常显示为“没有可测量的效果”。这是回执在保持谨慎。
- 低于面板自身分辨率的模式，可能让文字看起来发虚。Hedroom 会在建议中说明。
- 如果 Hedroom 在这 15 秒内崩溃，未确认的模式会在下次启动或你退出登录时恢复，而不是立刻恢复。
免费还是 Pro
读数和建议是免费的。“试一试”属于 Pro。“撤销”永远不会被锁定。
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.