Why does my PC slow down during video exports?

Your PC may feel normal while browsing or editing, then slow down as soon as you export a video. The fans may get louder, the progress bar may crawl, or the whole computer may become sluggish. That pattern can point to heat or power limits, but export settings and storage can cause similar symptoms.

Start by checking whether performance drops as the computer warms up. The Overheating Test applies a short heavy workload to see if performance slows when the computer is hot. It cannot read exact temperatures or recreate the same work as a video editor, so use it alongside a repeatable export.

Check what changes during an export

1. Repeat a short export. Use the same project, a one-minute section, the same output settings, and the same destination drive. Note how long it takes and whether the slowdown begins immediately or after several minutes.
2. Check the computer's workload. On Windows 11, open Task Manager with Ctrl + Shift + Esc and select Performance. On a Mac, open Applications › Utilities › Activity Monitor. Watch CPU, memory, and disk activity while the export runs.
3. Run a separate heat check. Stop the export and let the computer cool down. Then open the Overheating Test and run its short full-load check. Do not run it at the same time as a video export, because the extra workload would distort both results.
4. Compare one setting at a time. Export the same short section with hardware encoding enabled, then disabled, if your editor offers that setting. Keep the codec, resolution, and destination unchanged so you can compare the results fairly.

Keep the original project and source files unchanged while testing. If the PC becomes extremely hot, shuts down, or shows a temperature warning, stop the test and let it cool instead of repeating the workload.

What the results mean

The export starts quickly, then slows down

A drop after a few minutes can happen when the processor or graphics chip heats up and reduces its speed to protect itself. This is called thermal throttling. A power limit can produce a similar pattern, particularly on a laptop running on battery. If the Overheating Test also slows during its load, heat is a stronger possibility, but the test does not identify a faulty fan or report an exact temperature.

The export is slow from the beginning

A steady slowdown from the first moment is less suggestive of heat buildup. The project may use effects that are demanding to calculate, the editor may not be using hardware encoding, or the computer may be running in a low-power mode. Compare a short export with hardware encoding on and off, changing only that option.

The disk stays busy or the computer runs out of memory

If disk activity remains high, the editor may be reading source files or writing a large temporary file while other work competes for the same drive. If memory use is near its limit, the operating system may move data to storage, which can make the whole computer feel slow. A Storage Test can compare large-file disk speed and small writes, but it does not diagnose drive health or measure performance during your export.

The test is steady, but the editor slows down

The browser test uses a different workload from a video editor. If it stays steady while exports slow, that does not rule out a heat issue under the editor's particular mix of CPU and graphics work. It can also mean the bottleneck is the project, a background task, or a setting in the editor.

How to fix the slowdown

1. Give the computer clear airflow. Put a laptop on a hard, flat surface rather than a bed or blanket, and keep vents clear. Move a desktop away from a tight cabinet and check that its vents are not blocked by dust. Do not open a laptop unless you know how to service it safely.
2. Connect the charger and check power mode. On Windows 11, open Settings › System › Power & battery › Power mode and choose a performance-focused option when available. On a Mac laptop, open System Settings › Battery and check Energy Mode if that option appears. A high-performance mode may use more power and create more heat.
3. Close tasks that compete with the export. Pause large downloads, cloud backups, and other demanding apps, then repeat the same short export. Task Manager or Activity Monitor can help identify a process using a lot of CPU, memory, or disk time.
4. Check the export settings. Test a lower resolution or a less demanding effect on a copy of the project. If your editor has hardware encoding, compare it with software encoding. The faster option depends on the computer, graphics support, and codec, so verify the result rather than assuming one mode is always faster.
5. Use a local drive with room to work. Avoid exporting to a nearly full drive, a slow external device, or a drive connected through a questionable hub. Make sure the destination has enough free space for the video and temporary files. Back up important footage before changing drives or storage settings.
6. Update the editor and graphics driver. Install updates from the computer or graphics maker's official update tools, then restart before comparing another export. Change one thing at a time so you can tell whether it helped.

When to suspect a hardware problem

Heat is more concerning if the computer repeatedly shuts down, displays a temperature warning, becomes unusually hot near its vents, or slows sharply even during light work. Loud fans alone do not prove a fault. If a laptop's slowdown continues after you clear its vents and use it on a hard surface, or a desktop fan does not spin when it should, stop running heavy tests and arrange service. A repair shop can check cooling hardware and internal temperatures directly. A browser test cannot confirm a failed fan, blocked heatsink, or damaged processor.

Why an export differs from a browser test

Video exports can load several parts of a computer at once. Decoding source clips, applying effects, encoding the output, and writing the file may use different combinations of processor, graphics chip, memory, and storage. The balance changes with the editor, codec, resolution, and project. The Overheating Test is useful for spotting a general slowdown under load, but a repeatable export is the best way to check whether the change affects your actual work.

Compare short exports with the same settings and let the PC cool between heavy tests if it is already running hot.