Latency and Timers

Understanding Latency and Timers

Medium

Learn about system latency factors: interrupts, DPC, timers, and message handling

💡 Understanding latency sources helps identify optimization opportunities

System Latency Sources

ℹ️

System latency comes from multiple sources: - Interrupt processing (IRQ/DPC) - Windows timer resolution (15.625ms default) - High Precision Event Timer (HPET) overhead - Windows message queue processing Each can be optimized for lower latency gaming.

Latency Impact on Gaming

ℹ️

Lower latency means: - Faster mouse/input response - Lower ping in multiplayer games - Reduced frame timing jitter - Better competitive gaming performance

Disable Dynamic Tick

Medium

Configure interrupt priority and disable dynamic tick for consistent timing

💡 Ensures consistent interrupt processing and reduces timing variations

Disable Dynamic Tick

DisableDynamicTick forces Windows to use fixed 15.625ms timer instead of dynamic adjustment. This provides more consistent timing for gaming.

PowerShell / CMD

 $path = "HKLM:\SYSTEM\CurrentControlSet\Control\KernelVelocity"
New-Item -Path $path -Force | Out-Null
New-ItemProperty -Path $path -Name "DisableDynamicTick" -PropertyType DWord -Value 1 -Force

Important

⚠️

Requires administrator privileges and Windows restart. Helps consistency in frame timing.

Configure DPC Watchdog

Medium

Adjust DPC watchdog profile for lower latency

💡 Prevents DPC timeout issues and improves interrupt response

Set DPC Watchdog Offset

DPC (Deferred Procedure Call) Watchdog monitors interrupt processing time. Increasing the offset prevents watchdog timeouts.

PowerShell / CMD

 $path = "HKLM:\SYSTEM\CurrentControlSet\Control\Session Manager\kernel"
New-ItemProperty -Path $path -Name "DpcWatchdogProfileOffset" -PropertyType DWord -Value 10000 -Force

Value Meaning

ℹ️

10000 (0x2710) allows up to 10 microseconds for DPC processing before timeout.

Set Low Timer Resolution

Medium

Reduce Windows timer resolution from 15.625ms to 1ms or 0.5ms

💡 Dramatically improves input responsiveness and frame consistency

Understanding Timer Resolution

ℹ️

Default Windows timer resolution: 15.625ms (64 Hz) Gaming optimal: 1ms (1000 Hz) Aggressive: 0.5ms (2000 Hz) Lower timer resolution = more frequent timer interrupts = lower latency

Set Timer Resolution to 0.5ms

Use bcdedit commands to set timer resolution to 0.5ms, the most aggressive gaming optimization.

PowerShell / CMD

 bcdedit /set disabledynamictick yes
bcdedit /set useplatformclock true

Important

⚠️

These bcdedit commands require administrator privileges and Windows restart.

Timer Resolution Tools

Medium

Use third-party tools to adjust timer resolution in real-time

💡 Allows dynamic timer adjustment without system restart

Recommended Tools

ℹ️

- TimerResolution by Lucas Hale: GUI tool for real-time timer adjustment - HPET Utility: Direct hardware timer access These tools bypass the 15ms default and work immediately without reboot.

Using TimerResolution

ℹ️

Download TimerResolution, set to 0.5ms or 1ms, and it immediately takes effect. Recommended for testing before permanent bcdedit changes.

Disable HPET

Medium

Disable High Precision Event Timer which can introduce latency

💡 On most modern systems, HPET adds latency rather than helping

Disable HPET via Boot Configuration

Remove useplatformclock setting to disable HPET (High Precision Event Timer) at the firmware level.

PowerShell / CMD

bcdedit /deletevalue useplatformclock

Alternative: Disable via Device Manager

Disable the High Precision Event Timer device in Device Manager as an alternative method.

PowerShell / CMD

 Get-PnpDevice | Where-Object {$_.FriendlyName -like "*High Precision Event Timer*"} | Disable-PnpDevice -Confirm:$false

Compatibility Warning

⚠️

On very old systems or notebooks, HPET may be necessary. Test stability after disabling before making permanent.

Configure Windows Message Priority

Medium

Reduce Windows message queue latency with Win32PrioritySeparation

💡 Improves window message processing speed for faster input response

Set Win32PrioritySeparation for Gaming

Win32PrioritySeparation controls foreground vs background process priority. Value 38 (0x26) is optimal for gaming.

PowerShell / CMD

 New-ItemProperty -Path "HKLM:\SYSTEM\CurrentControlSet\Control\PriorityControl" -Name "Win32PrioritySeparation" -PropertyType DWord -Value 38 -Force

Common Values

ℹ️

26 (0x1A): Balanced 38 (0x26): Gaming (increased foreground priority) - Recommended 40 (0x28): Maximum foreground priority (aggressive)

Configure IRQ Priority

Medium

Set high priority for network and GPU interrupt handling

💡 Ensures network and GPU interrupts are handled quickly

Set IRQ Priorities

IRQ8 typically handles system timers, IRQ16 handles PCI-E devices like network and GPU. Set high priority for gaming devices.

PowerShell / CMD

 $path = "HKLM:\SYSTEM\CurrentControlSet\Control\PriorityControl"
New-ItemProperty -Path $path -Name "IRQ8Priority" -PropertyType DWord -Value 1 -Force
New-ItemProperty -Path $path -Name "IRQ16Priority" -PropertyType DWord -Value 2 -Force

Priority Values

ℹ️

Higher values = higher priority. Value 1-2 is safe range for gaming optimization.

Enable MSI Mode

Medium

Enable Message Signaled Interrupts for PCIe devices

💡 Reduces latency by using message-based instead of pin-based interrupts

What is MSI?

ℹ️

Message Signaled Interrupts (MSI) allows devices to signal interrupts via message delivery instead of dedicated interrupt pins. This reduces latency and contention.

Enable MSI for Gaming

ℹ️

Use MSI Utility or registry editing to enable MSI on: - Network adapter - GPU - USB controller Most gaming devices benefit from MSI mode.

Note

ℹ️

MSI mode is typically enabled by default on modern gaming hardware. Check Device Manager > Properties > MSI Support tab.

Verify Latency Settings

Medium

Check that all latency optimizations were applied

💡 Confirms configuration changes took effect

Check Dynamic Tick Disabled

Verify DisableDynamicTick is set to 1.

PowerShell / CMD

Get-ItemProperty -Path "HKLM:\SYSTEM\CurrentControlSet\Control\KernelVelocity" -Name "DisableDynamicTick"

Check DPC Watchdog

Verify DPC Watchdog profile offset is set.

PowerShell / CMD

 Get-ItemProperty -Path "HKLM:\SYSTEM\CurrentControlSet\Control\Session Manager\kernel" -Name "DpcWatchdogProfileOffset"

Check Timer Resolution

Verify bcdedit timer settings are applied. Check in System Information for Timer Resolution.

PowerShell / CMD

bcdedit /enum | findstr /i timer

Complete Latency Optimization

Medium

Apply all latency and timer optimizations at once

💡 Comprehensive latency reduction in one script

Complete Optimization Script

This script applies all recommended latency and timer optimizations.

PowerShell / CMD

 # Disable Dynamic Tick
$path = "HKLM:\SYSTEM\CurrentControlSet\Control\KernelVelocity"
New-Item -Path $path -Force | Out-Null
New-ItemProperty -Path $path -Name "DisableDynamicTick" -PropertyType DWord -Value 1 -Force

# Configure DPC Watchdog
$path = "HKLM:\SYSTEM\CurrentControlSet\Control\Session Manager\kernel"
New-ItemProperty -Path $path -Name "DpcWatchdogProfileOffset" -PropertyType DWord -Value 10000 -Force

# Configure Win32PrioritySeparation for Gaming
New-ItemProperty -Path "HKLM:\SYSTEM\CurrentControlSet\Control\PriorityControl" -Name "Win32PrioritySeparation" -PropertyType DWord -Value 38 -Force

# Configure IRQ Priorities
$path = "HKLM:\SYSTEM\CurrentControlSet\Control\PriorityControl"
New-ItemProperty -Path $path -Name "IRQ8Priority" -PropertyType DWord -Value 1 -Force
New-ItemProperty -Path $path -Name "IRQ16Priority" -PropertyType DWord -Value 2 -Force

# Set Timer Resolution via bcdedit
bcdedit /set disabledynamictick yes
bcdedit /set useplatformclock true

Write-Host "All latency optimizations applied. Please restart Windows."

After Running Script

⚠️

Restart Windows for all changes to take effect properly.

Latency and Timers Best Practices

Medium

Important guidelines for applying latency optimizations

💡 Prevents issues and ensures optimal configuration

Before Making Changes

⚠️

1. Create a system restore point 2. Run PowerShell as Administrator 3. Test in safe mode first if concerned about stability 4. Have driver CDs/downloads ready for GPU and network 5. Note all original settings before changes

System Restart Required

⚠️

All these changes require a complete system restart to take effect. Plan accordingly.

Compatibility Notes

ℹ️

- Works on Windows 7, 8, 10, and 11 - Some very old systems may need HPET enabled - Virtual machines may not support all changes - Some settings require specific hardware support

Testing Results

ℹ️

Expected improvements: Reduced input latency (5-10ms typical), lower frame time consistency, better ping stability. Results vary by hardware and game.

Latency and Timers

Understanding Latency and Timers

System Latency Sources

Latency Impact on Gaming

Disable Dynamic Tick

Disable Dynamic Tick

Important

Configure DPC Watchdog

Set DPC Watchdog Offset

Value Meaning

Set Low Timer Resolution

Understanding Timer Resolution

Set Timer Resolution to 0.5ms

Important

Timer Resolution Tools

Recommended Tools

Using TimerResolution

Disable HPET

Disable HPET via Boot Configuration

Alternative: Disable via Device Manager

Compatibility Warning

Configure Windows Message Priority

Set Win32PrioritySeparation for Gaming

Common Values

Configure IRQ Priority

Set IRQ Priorities

Priority Values

Enable MSI Mode

What is MSI?

Enable MSI for Gaming

Note

Verify Latency Settings

Check Dynamic Tick Disabled

Check DPC Watchdog

Check Timer Resolution

Complete Latency Optimization

Complete Optimization Script

After Running Script

Latency and Timers Best Practices

Before Making Changes

System Restart Required

Compatibility Notes

Testing Results

Accessibility Tools