[Bug] Desktop freezes/lag during Claude Code output on high refresh rate + high resolution displays

[Evopower]

Preflight Checklist

• I have searched existing issues and this hasn't been reported yet
• This is a single bug report
• I am using the latest version of Claude Code

What's Wrong?

When Claude Code is outputting text (especially during tool execution or streaming responses), the entire desktop becomes extremely laggy/unresponsive. This is especially noticeable on high refresh rate displays.

Environment

• Version: 2.1.77
• OS: Windows 11 Pro (Build 26200)
• Install: winget (Anthropic.ClaudeCode)
• Display:
  • Primary: Intel Arc A770 GPU, 3840x2160 (4K) @ 165Hz
  • Secondary: Intel UHD Graphics 770, 1920x1080 @ 165Hz
• Terminal: Windows Terminal (latest)
• Shell: PowerShell 7 / cmd.exe

Observed Behavior

During Claude Code output (tool execution, streaming responses), the entire desktop experiences severe lag:

• Mouse cursor stutters
• Other applications become unresponsive
• Keyboard input is delayed
• Audio/video playback may stutter

The issue is much more pronounced on the 4K@165Hz display.

Expected Behavior

Claude Code output should not affect overall system responsiveness. The desktop should remain fluid even during heavy terminal output.

Steps to Reproduce

1. Start Claude Code session
2. Execute any command that produces significant output (e.g., running a script, reading multiple files, tool execution with verbose output)
3. Observe desktop responsiveness during output

Additional Information

The issue seems related to how Claude Code handles terminal rendering - it appears to be a full-screen redraw architecture that causes blocking and high CPU/GPU usage during output.

[YoussofKhawaja]

I'm experiencing the same issue, the desktop lags, and the display flickers.

[avi12]

Huh, I thought it's an issue with my hardware even though it's powerful, I'm glad I'm not the only one to experience this

[Evopower]

Still reproducing on v2.1.77 and later versions.

Hardware: Intel Arc A770 GPU, 4K@165Hz primary display + 1080p@165Hz secondary, Windows 11 Pro.

The entire desktop freezes during streaming output — not just the terminal. Mouse cursor stutters, other apps become unresponsive, audio/video playback stutters. Issue is significantly worse on the 4K@165Hz display.

This appears to be a rendering architecture issue where terminal output causes system-wide blocking, likely due to full-screen redraw behavior.

Would appreciate an official response or triage. Happy to provide any additional diagnostics.

[Mezmeer1]

I've been having the same issue. I upgraded my network card and it's gotten better. I think it might have something to do with the packet bursts and how IRQs are handled? IDK maybe I'm wrong and it hasn't gotten better. It definitely seems like it's gotten better though, the desktop lagging has gotten smoother whereas before the upgrade I would have everything freeze for half a second, go, freeze, go. Now it's more like stuttering.
CPU:12th Gen Intel(R) Core(TM) i7-12700
GPU:NVIDIA GeForce RTX 3080
HDD: WDC WD10EZEX-60WN4A2 & NVMe WD WD_BLACK Gen4 SDCPNRY-1T00-1106
Network: Intel(R) Wi-Fi 7 BE200 320MHz
Motherboard: HP 894A
OS: Microsoft Windows 11 Pro 10.0.26200

[github-actions]

Closing for now — inactive for too long. Please open a new issue if this is still relevant.

[adefirmanf]

Can reopen the issue, faced similar issue?

[Mezmeer1]

So, I forgot all about this thread. I've just been suffering with this issue. I mistakenly thought it was gone due to a reboot when I installed my new NIC.
I think I'm (in my free time) coming up with an answer. I read somewhere that somebody said something about high refresh rate.
My setup (again) Win11 26200, 120Hz, hybrid graphics (Intel UHD 770 + 3080). Same stutter in Windows Terminal, PS5, and PS7, so the terminal doesn't matter either.

One thing I haven't seen mentioned: it gets worse the longer the machine has been up, and rebooting fixes it temporarily. Fresh boot, I can go all day fine. After 2-3 days of uptime it's stuttering constantly.

I dug into it and found kernel memory (nonpaged pool) climbing steadily and never getting released - up to 4.4GB over about two days of light claude code usage. When I broke it down, most of the growth is coming from the graphics driver, and some of it from dxgkrnl / dxgmms, (DirectX layer that every GPU goes through). Which might explain why we're both seeing this on different hardware.

Also worth noting: I ruled out output volume and disk reads by dumping 200k lines to the console and hammering the filesystem with reiterative get-child listings set to loop, and neither caused any stutter at all.

I'd be interested to see if you could see if your paged keeps growing. If you want to check whether you've got the same thing, run this in PowerShell (no admin needed):
powershell"{0:N0} MB nonpaged | uptime {1:N1}h" -f ((Get-Counter '\Memory\Pool Nonpaged Bytes').CounterSamples.CookedValue/1MB), ((Get-Date)-(Get-CimInstance Win32_OperatingSystem).LastBootUpTime).TotalHours

Output looks like: 2,589 MB nonpaged | uptime 26.5h
Use it to check on things periodically. Of couse claude can help you chase the issue. Mine goes up about 60 MB/hour and doesn't come back until I reboot it was 2,589 MB at 26h uptime and 4,398 MB at 54h.