Message Signaled Interrupts vs. Line-Based (possible latency reduction)

[Starship Krupa]

This is another system tuning tweak. From Vista onward, Windows has supported Message Signaled Interrupts on the PCI and PCIe buses.

This is basically the 21st century solution to the old PC issue of conflicting or shared IRQ's. In simplistic terms, it allows over 200 "IRQ's" and a different way of using them.

I don't remember where I first heard about the technology, but I found a few articles on it, plus a utility that will allow you to view whether a given PCIe device is using message signaled or line-based and set it accordingly:

https://forums.guru3d.com/threads/windows-line-based-vs-message-signaled-based-interrupts-msi-tool.378044/

I ran it on my new system and found that my GT 1030 graphics card was sharing IRQ11 with my Firewire adapter. Hmm. The Firewire adapter only supports line-based, but the video card switched over to message signaled and now has its own IRQ.

Kinda funny, I remember way back in the day, first setting IRQ jumpers, then when Windows 95's plug and play moved IRQ sharing more to the OS. We'd still get conflicts where the sound card and the video card always seemed to want to share IRQ 11.

Try it, and try running LatencyMon before and after and see what you get.

(MSI Tool also lets you assign a priority to each device's interrupt, which might allow further tuning for DAW use, but I'm going to have to study up on that before I try it)

[Xoo]

Ditto - I use MSI Util and have for years.