Why is Word using so much CPU?

High CPU usage is typically caused by background spell checking on large documents, add-in processes, hardware graphics acceleration issues, or corrupted document elements that Word repeatedly tries to process.

Fix: Microsoft Word Using 100% CPU

Why Word Uses Excessive CPU

High CPU usage from Word makes your entire computer sluggish. Here are the common triggers and how to fix each one.

Étapes de résolution

Step 1: Disable Hardware Graphics Acceleration

Go to File > Options > Advanced
Scroll to the Display section
Check Disable hardware graphics acceleration
Click OK and restart Word

Step 2: Disable Background Spell Checking

For large documents, spell checking can consume significant CPU:

Go to File > Options > Proofing
Uncheck Check spelling as you type
Uncheck Mark grammar errors as you type
Run spell check manually when needed with F7

Step 3: Check Add-ins

Open Task Manager and note Word’s CPU usage
Close Word, reopen in Safe Mode (winword /safe)
Open the same document and check CPU usage
If lower in Safe Mode, disable add-ins via File > Options > Add-ins

Step 4: Simplify the Document

If the issue is document-specific:

Try selecting all content (Ctrl+A) and pasting into a new blank document (Ctrl+Shift+V for unformatted)
If CPU normalizes, the original document has corrupted formatting
Reapply formatting in the new document

Step 5: Check for Updates

Go to File > Account > Update Options > Update Now
High CPU bugs are often fixed in Office updates

Prévention

Keep documents under 100 pages when possible
Compress images before inserting
Avoid deeply nested tables
Update Office regularly