I'm a competitive gamer (FPS, ARPG, RTS) of many years, and here's my suggestions for DPC latency:
1) Much of the internet is misinformation when it comes to performance tweaking, and stuff from gamers on social platforms typically won't reduce latency, because most people just regurgitate things without actually testing it, so a lot of bad advice circulates around as if it were fact for many years, but so many tweaks don't work on Windows 10/11 or don't work the way people think they do. It takes many tweaks to lower latency in a meaningful way, so anyone claiming a single tweak or two fixes all their problems is usually wrong and doesn't understand the underlying condition.
2) Windows 11 has more latency (
link1) than Windows 10, so if latency is a main concern the first step is to switch operating systems, especially since it's free, because Windows 11 licenses can be used on Windows 10.
3) Here's a guide (
link2) I wrote, which has tons of tweaks that are confirmed to lower latency.
4) This guide (
link3) will create a custom Windows that has all my recommended tweaks, including all of them from the DPC latency guide. The only thing it doesn't include from the DPC latency guide is BIOS tweaking, since that has to be done manually on every computer.
5) Improving latency is as simple as reducing overhead (processes, handles, threads, memory), and how you get there can vary wildly. Some people utilize component removals to do it, while some people use registry keys, and others use both. There's also the hacky approach, such as manually deleting files to break features and using a bunch of scripts or tools, but that's usually a sign of bad tweaking and inexperience.
6) There are more guides and related discussions in the
Gaming Lounge.