The most common reason so many people have input lag problems these days.

[DJHarmonics]

I'll keep it as simple as I can.

The reason most of you have input lag is due to a high number of reasons all related to emi, the most common is electrical interference due to poor power factor/high harmonics and grounding.

A common problem people are having is harmonic distortion on their electrical system. Harmonics=elevated electrical and magnetic fields that interact each other, causing eddy currents which increases the resistance of the grounding system which then can cause looping currents within the system. This effect causes common mode and differential mode noise in the electrical system. Which then causes elevated electric and magnetic fields, or simply put, emi. It's an issue in almost every home.

Computers use smps (switch mode power supplies), which rely on capacitors to reduce common mode electrical noise. They work by shunting the noise from hot and neutral to the ground wire. The problem with this is, when you have high resistance on your grounding system the electrical noise shunted by those capacitors no longer travel down the ground wire, they travel through the shields of your cables, your computer case, your floor, ceiling, furnace duct, the air etc etc.. any and all paths of least resistance back to the source.
The effect is ground fault currents, which means elevated electrical fields, that further interact with the magnetic fields that further increases the problem.
This is the reason so many mention their PC running great for the first few minutes to then have the input lag suddenly return. It's the noise from the computer looping through the electrical system, increasing and increasing the electrical noise.
All devices in the electrical system are effected from the effects of this interaction which all further aggravate the situation by dumping their noise in the system.

Not everyones situation is going to be exactly as explained, and not every emi problem is as complicated. But they are almost all related to electrical noise in your electrical system or circuit, and all have solutions.

There is no 1 fix solution, but there is easy, simple things you all can do to improve the problem if not, fix it completely.

Attacking the source of emi instead of trying to mitigate the symptoms is how to properly do it. And it's not as hard as you might think.

There is a lot of solutions to mitigate emi if anyone has any questions.
I can answer a lot of questions and sort any emi problem. I can explain simple tricks to easily identify sources of emi and how you can easily reduce or remove them.

[d-unknown]

so that means that if you make sure that your ground is good and have as low as possible resistance (<100ohms) the issue will be highlly mitigated ?, it's funny that you talk about that, because i've ordered a ground resistance tester today
personnaly i've a dedicated power line from the utillity ,only for my pc, , i've almost 0v between neutral & earth during the day, but 35v by night it's probably due to the public lightning, and there is nothing i can do about that , at least i don't know what to do next

btw i've a 1000va medical grade isolation transformer , which according to the greenwave emi tester, reduces significantly the noise, but it doesn't make any positive effect on input lag or desync

i'm seriously thinking going off grid with solar panels, but it's a 3000$ investment and i have no idea if it's worth it

your knowledge is welcome here, as you may see , every one here is struggling with that issue

[Mugabi]

so that means that if you make sure that your ground is good and have as low as possible resistance (<100ohms) the issue will be highlly mitigated ?, it's funny that you talk about that, because i've ordered a ground resistance tester today
personnaly i've a dedicated power line from the utillity ,only for my pc, , i've almost 0v between neutral & earth during the day, but 35v by night it's probably due to the public lightning, and there is nothing i can do about that , at least i don't know what to do next

btw i've a 1000va medical grade isolation transformer , which according to the greenwave emi tester, reduces significantly the noise, but it doesn't make any positive effect on input lag or desync

i'm seriously thinking going off grid with solar panels, but it's a 3000$ investment and i have no idea if it's worth it

your knowledge is welcome here, as you may see , every one here is struggling with that issue

I know 3 dudes who got solar panels without a difference. Many dudes who play off grid battery. Don't do it bro.

[spkii]

Then? what do you suggest?

[ZINZIRIO]

I bought an emi filter hoping to notice some difference... I am convinced that the ground has a lot to do with it. For 3 days when I put a dedicated ground my game worked as it should but then everything fills up with dirty energy again... A My point of view, if there is a solution, it depends on the land we have.

[greenenemy]

Q: What are typical input lag values in miliseconds of affected PC before and after your fixes?

[DJHarmonics]

so that means that if you make sure that your ground is good and have as low as possible resistance (<100ohms) the issue will be highlly mitigated ?, it's funny that you talk about that, because i've ordered a ground resistance tester today
personnaly i've a dedicated power line from the utillity ,only for my pc, , i've almost 0v between neutral & earth during the day, but 35v by night it's probably due to the public lightning, and there is nothing i can do about that , at least i don't know what to do next

btw i've a 1000va medical grade isolation transformer , which according to the greenwave emi tester, reduces significantly the noise, but it doesn't make any positive effect on input lag or desync

i'm seriously thinking going off grid with solar panels, but it's a 3000$ investment and i have no idea if it's worth it

your knowledge is welcome here, as you may see , every one here is struggling with that issue

Yes, a lower resistance ground will be beneficial, for high frequency noise the larger the ground plane the better.
My guess for the increase neutral to ground voltage is the added noise at the utility transformer from street lights, teslas being charged, furnaces turning on etc etc.. which can cause ground potential change.

The isolation transformer will only reduce high frequency noise, so it wont do too much to help the situation unless you are on a single phase electrical system with the neutral and ground bonded at the main panel. Your PC powersupply is already really good at filtering out noise.
The cause of your problem is most likely primarily emissions from your surroundings. Nearby circuits and devices, wifi signals etc, and lack of shielding at your PC. A very easy trick and one of the best tools to quicky identify the level of electrical noise and sources of noise in your environment is a simple am radio tuned to 500khz or the lowest channel available.
Another huge problem is the computer being close proximity to the wiring in the walls and nearby circuits that will have electrical fields which can cause capacitive coupling to unshielded and unproperly grounded cables and devices.

What I would do is, filter out noise from big sources in the house with emi filters. Avoiding too many filters with y capacitors especially if your grounding isn't the best. Film capacitors work well for removing differential mode noise, placing them around your circuit while keeping them off your circuit is best. Film capacitors will slightly increase the neutral to ground voltage on the circuit they're place on so it's best to place them on only the surrounding circuits and nearby noisy devices.

[DJHarmonics]

Q: What are typical input lag values in miliseconds of affected PC before and after your fixes?

It doesn't quite work in a delay reduction average. What it does do is, reduce or remove all the bit rate errors in the system reducing jitter. It's more about mouse inconsistency than an exact delay reduction, but it's not just the mouse delay that you will perceive as mouse input lag. It effects a longer line of events that that all contribute to the location of the curser on screen. Ram, cpu, gpu, monitor, game logic etc.. It decreases the system interrupts/dpc latency as well.

[Fishie]

I bought an emi filter hoping to notice some difference... I am convinced that the ground has a lot to do with it. For 3 days when I put a dedicated ground my game worked as it should but then everything fills up with dirty energy again... A My point of view, if there is a solution, it depends on the land we have.

Not necessarily. Doing Any hardware or software change temporarily fixes the problem