Specs:
CPU: AMD Ryzen 7800x3D
RAM: G.Skill DDR5 6000 2 x 32 GB 30-40-40-96
GPU: Gigabyte Gaming OC RTX 4090
SSD: Samsung 980 Pro SSD
OS: Windows 10
Motherboard: Gigabyte B650 Aorus Elite AX
I've been dealing with persistent input lag and stuttering, sometimes one without the other or both for about 2.5 years now, in game and in normal use. My inputs feel heavy and out of sync. I am beyond my wit's end - I need any help I can get. Assume that everything I list here, I tried changing and testing individually with restores/backups where applicable - I haven't changed multiple things at once. I don't have any sense of consistency with this PC, something I think could be helping usually feels either how it was, or terrible the next day. Some things might seem stupid but I did it to remove variables or by some advice. I've tried completely wiping windows and my drive and reinstalling Windows 10 (Windows 11 felt 2x as bad as 10) many times over the past few years, and I have tested without changing any settings/optimized defaults.
Important to note:
I don't know if I'm imagining things, but my PC defininetely seems to run better at night time with no difference in my settings. I've done benchmarking at all times of day and nothing stands out to me, the thermals and speeds seem relatively the same. The following settings are just what I remember, many other things have been tested and reverted. It probably seems like I'm just tweaking every setting I can find but this is since I built the PC, but this is over the full course of time since building it.
About a year after having the PC, my RAM died (DDR5 6000, 2 x 16 GB kit of G.Skill), so I swapped it out for my current 2 x 32 GB kit. Last month I borrowed a kit of RAM (DDR5 6000, 2 x 16 GB) and my PC felt smoother overall, but the same issues were still present. Earlier this month I was informed it could be the CPU's IMC, so I tried swapping out my 7800x3D for a 7700x, nothing. I've tried booting with 1 stick of my current RAM, it's more consistent but way too slow. These issues are persistent across multiple fresh installs of Windows on different SSDs. I've replaced my keyboard, headphones and mousem, and after testing my mouse's polling with MouseTester, replacing the USB-C cord to resolve instability.
* = I perceived it to help
** = I am certain it helped
Motherboard
Clearing CMOS when necessary
*Updating BIOS
Tried different cable configurations in rear IO ports
Checked all cable connections to ensure nothing is loose both in rear IO ports and motherboard
CPU
Reapplied thermal paste, reseated CPU and ensured CPU cooler is mounted firmly
*Increasing SOC voltage by .05 increments up to 1.25v
PBO at a few of the automatic levels, and manually with a negative curve optimizer in increments of 5
*Increasing Load Line Calibration level
*Disabling C-States
Spread Spectrum enabled/disabled (feels more consistent when on, but unbearably slow)
Resizable BAR, above 4G Decoding, Disabling SMT, Disabling SVM (frametime/latency tradeoff)
GPU
*Manually tested 20+ supported GPU drivers (DDU, NVCleanstall) with recommended settings and power management set for performance, took notes for each version
Flashing GPU with updated firmware (checked the manufacturer's specifications, not a random version)
*Forcing higher clock/memory speeds with nvidia-smi via command line (MSI Afterburner's monitoring seemed to conflict with I assume the kernel anti-cheat)
**Scaling mode set to display, no scaling option checked
RAM
Enabling EXPO (DDR5 6000, 2 x 32 GB)
Trying lower speeds at 4800, 5200, 5600
**Low latency mode enabled
**High bandwidth enabled
System
Setting interrupt affinity in assorted orders and enabling MSI mode for peripherals and GPU
**Performance oriented power plan (unnecessary interrupts and power management/sleep settings disabled)
**Disabling power management features for all devices I use in Device Manager
**Ending/disabling background tasks I know I don't need in task manager
*Various recommended HPET settings
**Disabling MPO overlay
Mouse + Keyboard
Lower polling rates
**Removing all peripheral related software
Network
**Removing Wi-Fi and using ethernet
**Reducing bufferbloat with a few settings via adapter options