PC lagging when gaming: which kind of lag, and how to fix it

Four problems that all get called lag

If your problem is the second row, the random FPS drop guide is the better starting point, and the fourth row belongs to fixing high ping. This page concentrates on system slowdown and input lag, which are the two that come from the PC itself rather than from the game's frame rate or the network.

Check for a whole-system slowdown

A PC that slows down as a whole while a game is running is short of something, and Task Manager shows what. Leave it open on a second monitor, or switch to it the moment the slowdown starts, and look at the Performance tab:

• Memory close to full, with the "committed" figure near its limit, means Windows is moving data to the page file and everything waits on storage.
• Disk active time pinned at its maximum means the drive cannot keep up, which on a hard drive can stall the whole system.
• Processor busy even before the game started means background software is eating into the capacity the game needs.
• Temperatures, shown in the GPU section and in tools like MSI Afterburner, reaching their ceiling means the hardware is slowing itself down.

Whichever line is at its limit when the lag appears is where to spend your effort. The next sections take them in turn.

Fix: not enough free memory

Modern games, a browser with many tabs, chat, a launcher and a recording tool can together outgrow the memory in a PC that seemed plentiful a few years ago. Close what you do not need before playing, especially browsers, which hold a surprising amount. Check Settings, Apps, Startup for programs that sit in memory from the moment you sign in.

Leave the page file on and managed by Windows. With it off, a PC that runs out of memory does not slow down gracefully; programs crash instead, as the page file reference explains. If memory is consistently near full in the games you play, adding memory is the real fix, and no setting substitutes for it.

Fix: a drive that cannot keep up

A game installed on a hard drive, a system drive close to full, or a drive busy with something else all show up as disk activity pinned at its maximum. Move your most-played games to an SSD if you have one. Keep a healthy amount of free space on the system drive, since Windows needs room for the page file, updates and caches. If the drive is busy before you even launch a game, look in Task Manager's Processes tab, sorted by disk, for the culprit: search indexing, a cloud sync, an antivirus scan or a launcher update are the usual ones.

This is also where a maintenance tool genuinely earns its place, clearing space that has built up over years. Gaming optimizers versus cleaners explains which kind of software suits this job.

Fix: input lag that is not a frame-rate problem

When the picture is smooth but your actions feel late, the delay is somewhere between your hand and the screen. Start with the display. Televisions and some monitors apply image processing that adds delay; a game mode or low-latency mode in the display's own menu turns it off. Check that Windows is running the monitor at its full refresh rate under Settings, System, Display, Advanced display, because a monitor left at a lower rate than it supports is a common and easily missed cause.

Traditional VSync can add noticeable delay because frames wait for the display. A frame cap just below the refresh rate, combined with variable refresh rate on a supporting monitor, usually gives smooth motion with less delay. On the input side, Windows' pointer acceleration changes how mouse movement translates to the cursor and many players prefer it off, as the mouse acceleration reference describes. If a wireless or USB device occasionally responds late after sitting idle, USB power saving may be putting its port to sleep; USB selective suspend covers that.

Fix: background work and heat

Background software that is harmless on the desktop can compete with a game for processor time. Before playing, close recording tools you are not using, pause cloud syncing and stop launchers downloading updates during play. Keep Game Mode on so Windows holds off installing updates mid-session.

Heat affects everything at once, which makes it easy to mistake for a software problem. If lag builds up over the first minutes of play and the fans get loud, clean dust from the heatsinks and fans and make sure air can move freely. On a laptop, check that it is plugged in and not in an energy-saving mode.

Rule out something that should not be there

If the PC is sluggish all the time and Task Manager shows unfamiliar processes using the processor or network, run a full scan with Windows Security or another reputable antivirus product before changing any performance settings. Unwanted software, including some so-called game boosters bundled with other downloads, is a real cause of system-wide slowdown, and no optimization makes sense on top of it.

Lag that started after an update

If the lag appeared suddenly, its timing is the first clue to follow. A Windows feature update can reset settings such as Game Mode, background recording and power mode, reinstall software you had removed, and leave indexing and maintenance tasks running for some hours afterwards while it settles. A new graphics driver can change per-game settings or clear shader caches. A game patch can simply make the game heavier than it was.

Give a PC a few hours after a major update before judging it, then recheck any settings you had changed, because they may no longer be as you left them. Reliability Monitor records when each update was installed, which makes it easy to line the start of the lag up against a specific change. If a graphics driver update looks responsible, installing the previous version from the card maker's website is a quick way to confirm it.

Where an optimizer fits

For lag, software helps less than most people expect. It cannot add memory, speed up a hard drive, cool a hot processor or fix the network. It can apply background and power settings, and on the input side switch off pointer acceleration and USB power saving in one place. Everything on this page can be done by hand for free.

JINSHI PC Tweaks is our product and covers those Windows settings. Every change is listed on the complete tweak list and reversible on its own. If you want them applied together once you have ruled out the hardware causes above, the JINSHI Tweaks homepage explains what PC Tweaks does. For deciding whether any tool is worth it, see how to choose a PC optimizer for gaming.