Try Linux to see, if issue is in Windows. You can use live-usb and try to measure DPC latency, if you can figure out how to do it on linux, tho you should probably use full installation and install graphic drivers first, you can use dual-boot it is not difficult to set-up... Wdf1000.sys is USB 3, try to disable legacy USB support in BIOS, or XHCI hand-off etc. Disable any USB ports you don't need. Again it may be your other USB devices causing the issue. I think you said that you saw drop after disconnecting some devices. USB audio is the worst! Disable all USB power savings using "Power Plan" app I sent you. You can also try to connect keyboard to different USB chipset, same USB chipset is usually horizontal line of USB ports, while USB ports vertically down, or up on a different line will be another chipset. Also uncheck turn device off, or allow to wake up computer for all: usb devices like mouse/keyboard and all USB and HID entries in device manager!!! There is still probably a lot of things you didn't try! BTW dxgkernel is now normal 250us isn't best, but it is ok. Tho you did test only 30 seconds. You need to test at least 15 minutes and doing nothing on background! Make sure to disable Intel turbo, whatever causes dynamic CPU frequency! And disable all power savings in BIOS and use ultimate power plan!!! You can also try timer resolution on 0.5ms, which also can reduce dpc latency. You can also try this link: Melody's Ultra Tweaks Pack - Basic Tweaks ctrl+f for Tell Windows to stop tolerating high DPC/ISR latencies. I think values there are meant to be used as 32 bit dword data-type, as it is most common data type, but not sure! First right-click given registry key you are editing and click export to backup for easy revert! Also did you switch your devices to MSI mode? Also what polling rate is your mouse and keyboard using?
