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[EMI] 1500mV When computer is running!!!
Posted: 18 Jan 2023, 23:52
by KingAzar
I got myself a tester and when my computer is not running, my EMI meter reads around 250mV; when it's on, it goes up to 1500mV. This is probably the cause of my lagging desync and mouse issue while probably my constant headache too!
From my understanding the EMI is coming from my PC when it’s on, using conditioner, filter etc. would be useless.
I bought my PSU 6 months ago and it's the Corsair HX850. Should I run a test without the 24 PSU ports connected to the motherboard or is the issue definitely the PSU? If so what would be my solution?

Video:
https://streamable.com/mrestd
Also, have a small computer Dell desktop that I use for Pfsense box and this one will get to 400mV (without my main PC running)
Re: EMI 1500mV When computer is running!!!
Posted: 19 Jan 2023, 03:39
Have you tried a "line filter"?
My hi-fi mains filter arrived yesterday. The game and the monitor feel much better. But this still needs a long-term test.
I bought the same EMI meter as you, but it's still on the way here. Then I can run tests and see how good this line filter is.
https://www.amazon.de/Dynavox-HiFi-Netz ... r=8-5&th=1
Update: don't buy!!!
The special thing about the mains filter is that each socket has its own filter. This filters out interference between the monitor and the computer.
Re: EMI 1500mV When computer is running!!!
Posted: 19 Jan 2023, 07:57
by MadMark
Did you try change PSU?
High EMI emissions can be typical for your PSU.
https://www.tomshardware.com/reviews/co ... 57-10.html
Re: EMI 1500mV When computer is running!!!
Posted: 19 Jan 2023, 09:48
by KingAzar
[email protected] wrote: ↑19 Jan 2023, 03:39
Have you tried a "line filter"?
My hi-fi mains filter arrived yesterday. The game and the monitor feel much better. But this still needs a long-term test.
I bought the same EMI meter as you, but it's still on the way here. Then I can run tests and see how good this line filter is.
https://www.amazon.de/Dynavox-HiFi-Netz ... r=8-5&th=1
The special thing about the mains filter is that each socket has its own filter. This filters out interference between the monitor and the computer.
Thanks for the advice, I will look into it.
My concerne here is that the EMI is emitted by my computer when it’s powered ON if I understand the EMI line tester unless I’m wrong. How the filter will correct the issue if the problem comes from my PC?
Re: EMI 1500mV When computer is running!!!
Posted: 19 Jan 2023, 09:49
by KingAzar
I have not but I can buy another one to try but I am not sure which one will be with low EMI.
Re: EMI 1500mV When computer is running!!!
Posted: 19 Jan 2023, 10:19
by MadMark
Re: EMI 1500mV When computer is running!!!
Posted: 19 Jan 2023, 12:45
by TheKelz
KingAzar wrote: ↑19 Jan 2023, 09:49
I have not but I can buy another one to try but I am not sure which one will be with low EMI.
https://www.tomshardware.com/reviews/co ... y-review/4
You should try HX1000i (the one I'm also planning to buy). At the bottom where the review ends, it says "EMI emissions are low". Also, many professional gamers who have no desync/input lag issue use this very same PSU, so at least it is trusted.
Re: EMI 1500mV When computer is running!!!
Posted: 19 Jan 2023, 13:53
KingAzar wrote: ↑19 Jan 2023, 09:48
[email protected] wrote: ↑19 Jan 2023, 03:39
Have you tried a "line filter"?
My hi-fi mains filter arrived yesterday. The game and the monitor feel much better. But this still needs a long-term test.
I bought the same EMI meter as you, but it's still on the way here. Then I can run tests and see how good this line filter is.
https://www.amazon.de/Dynavox-HiFi-Netz ... r=8-5&th=1
The special thing about the mains filter is that each socket has its own filter. This filters out interference between the monitor and the computer.
Thanks for the advice, I will look into it.
My concerne here is that the EMI is emitted by my computer when it’s powered ON if I understand the EMI line tester unless I’m wrong. How the filter will correct the issue if the problem comes from my PC?
Do not buy the line filter, it may not work. I picked up a network analyzer from work today. This shows no difference with or without a line filter. But I'm still waiting for the Emi Meter. If this confirms that this mains filter does not filter, I will send the mains filter back and build my own. And yes, you are right. If your power supply is causing the interference, the line filter won't help the computer.
Re: EMI 1500mV When computer is running!!!
Posted: 19 Jan 2023, 14:17
by KingAzar
[email protected] wrote: ↑19 Jan 2023, 13:53
KingAzar wrote: ↑19 Jan 2023, 09:48
[email protected] wrote: ↑19 Jan 2023, 03:39
Have you tried a "line filter"?
My hi-fi mains filter arrived yesterday. The game and the monitor feel much better. But this still needs a long-term test.
I bought the same EMI meter as you, but it's still on the way here. Then I can run tests and see how good this line filter is.
https://www.amazon.de/Dynavox-HiFi-Netz ... r=8-5&th=1
The special thing about the mains filter is that each socket has its own filter. This filters out interference between the monitor and the computer.
Thanks for the advice, I will look into it.
My concerne here is that the EMI is emitted by my computer when it’s powered ON if I understand the EMI line tester unless I’m wrong. How the filter will correct the issue if the problem comes from my PC?
Do not buy the line filter, it may not work. I picked up a network analyzer from work today. This shows no difference with or without a line filter. But I'm still waiting for the Emi Meter. If this confirms that this mains filter does not filter, I will send the mains filter back and build my own. And yes, you are right. If your power supply is causing the interference, the line filter won't help the computer.
Yeah if my EMI was high without anything plugged into the wall then it would make sense that a filter or other source could help. From my perspective, it's coming from my desktop.
My next test before ordering another PSU (this is going to be hard finding the right PSU) anyway, next test is to test the PSU without any component from my PC plugged in. I'm worried that the culprit is one of my hardware but maybe I'm overthinking?
Re: EMI 1500mV When computer is running!!!
Posted: 19 Jan 2023, 14:38
by assombrosso
It’s not the psu I think, could be gpu