--- title: "MSI mode: message-signalled interrupts and DPC latency" description: "What MSISupported does, why message-signalled interrupts reduce DPC latency, and why this is one of the few registry tweaks that still genuinely matters." url: https://frozentweaks.com/tweaks/msi-mode-interrupts author: Frost LIVE, Founder of Frozen Tweaks published: 2026-08-30 updated: 2026-10-08 category: "GPU" source: Frozen Tweaks (https://frozentweaks.com) --- # MSI mode: message-signalled interrupts and DPC latency **Short answer:** MSI mode sets MSISupported to 1 under the device's Interrupt Management\MessageSignaledInterruptProperties key, switching a device from legacy line-based interrupts to message-signalled interrupts. It reduces DPC latency, which is the mechanism behind audio crackling and micro-stutter. This is one of a small number of registry tweaks from the old era that still has a real measurable effect. ## In the app - Switch: Optimize Message Signal Interrupts (MSI) (GPU, Pro, Advanced) - Undo: Yes. Switching it off restores each device's previous MSI setting, which the app saves before changing it. - Catalog row: https://frozentweaks.com/tweaks#t-1004 ## What it does Legacy interrupts use physical lines that devices can share. When several devices share a line, the OS has to poll each to find out who signalled, which adds latency and can serialise unrelated work. Message-signalled interrupts let a device write directly to a memory address instead. No sharing, no polling, less time spent at high interrupt priority. The device instance path is different on every machine, which is why this is fiddly to do by hand. ## When it helps - Lower DPC latency, which is the direct cause of audio crackling accompanied by stutter. - Most noticeable on systems with many PCIe devices competing for interrupt lines. - Covers graphics cards and storage controllers, NVMe included, not just the GPU. ## When it hurts - A small number of older devices misbehave with MSI enabled. Symptoms range from device instability to failure to resume from sleep. - It has to be applied per device and re-applied if the device is reinstalled, which is exactly the maintenance problem manual tweaking has. - Not every device honours the setting even when the key exists. ## What it writes Read from the app's source. "Switching it off" is what the app writes when you turn the tweak off again. Registry values: | Key | Value | With the tweak | Switching it off | What it does | | --- | --- | --- | --- | --- | | `HKLM\SYSTEM\CurrentControlSet\Enum\\Device Parameters\Interrupt Management\MessageSignaledInterruptProperties` | `MSISupported` | `1` | Your previous value (saved before the change, or deleted if there was none) | Lets the device raise interrupts by writing a message rather than asserting a shared physical line. The app sets it for every graphics card, SATA controller and storage controller (NVMe included) that Windows lists. | | `HKLM\Software\FrostTweaks\MSI\` | `Prev` | `The previous MSISupported value` | Stays The previous MSISupported value (switching it off leaves it) | The app's own backup of the device's earlier setting, so switching the tweak off can put it back. | | `HKLM\Software\FrostTweaks\MSI\` | `PrevMissing` | `1` | Stays 1 (switching it off leaves it) | Written instead of Prev when the device had no MSISupported value, so switching the tweak off deletes it again. | Source: Tweaks/msi.hpp in the app's source, app 2.0.0, checked 2026-10-08. ## How to undo it Set MSISupported back to 0 for the affected device and reboot. Frozen Tweaks stores the previous value per device instance, including the case where the value did not exist at all, so switching it off restores the true original state rather than guessing at 0. ## Verdict Genuinely worth applying, and one of the few places where a tool is meaningfully easier than doing it by hand, because reverting requires remembering the prior state of every device you touched. ## Related guides - [How to Fix Stuttering and Frame Drops: Diagnose Before You Tweak](https://frozentweaks.com/guides/fix-stuttering-frame-drops) - [How to Reduce Input Lag on PC: The Whole Latency Chain](https://frozentweaks.com/guides/reduce-input-lag) - [Best NVIDIA Control Panel Settings for Gaming in 2026](https://frozentweaks.com/guides/nvidia-control-panel-best-settings) - [CS2 FPS Boost: Best Settings and Launch Options for 2026](https://frozentweaks.com/guides/cs2-fps-boost) ## More tweak explainers - [Multiplane overlay (MPO)](https://frozentweaks.com/tweaks/disable-mpo-multiplane-overlay) - [MSI mode for USB and NVMe](https://frozentweaks.com/tweaks/msi-mode-usb-nvme) - [TdrDelay](https://frozentweaks.com/tweaks/tdr-delay) --- Written by Frost LIVE, founder of Frozen Tweaks. Canonical version: https://frozentweaks.com/tweaks/msi-mode-interrupts