Ever since i've had my case open to measure something, a new piece of hardware, will it fit, etc, i have something happening that really restricts the performance and i'm not really sure what it is.

symptoms are, the whole system working at, maybe 10% of its capabilities. I checked this ingames where the result is laggy, and tried the benchmark as supplied by userbenchmark only to receive a score well below the average. Well well below the average.

The first time i spend a whole night troubleshooting ending swapping components of another pc in the household with compatible components and after several tries, replacing memory, cpu and gpu, uncoupling network and soundblaster card i finally came into a normal state. before of course after swapping i booted the system every time only to be confronted with the same sluggish smile.

With the system working ok again i swapped back to my configuration and everything stayed a ok. Until last night that is. Again the system won't move an inch forward and i fear my motherboard needs to be replaced.

Could anyone provide some pointers, maybe from experience or deduction that this is indeed the motherboard that is giving problems?

That's the problem with PCs that can make them be a nightmare: it's very hard to isolate what the cause of a problem is a lot of the time.

It could also be your power supply. Or it could be, as you said, your motherboard.

And it could also be problems with hard drive or your SSD being corrupted or damaged.

Probably the only way to tell for sure would be to keep swapping out components until you stop having problems --- that's IF it's a hardware problem, which it might not necessarily be (but it still could be).

Or it could also be problems with your OS being damaged.

Or it could also be problems with viruses.

Or it could be problems with software conflicts.

Or it could be problems with bad drivers.

There probably isn't any easy fix as to identifying what exactly the issue is though. You will probably have to work through it by trial & error.

Or maybe you aren't getting proper cooling.

Changing the physical configuration can change how the air circulates, or in some cases if wires are put in the wrong spot may some fans period while they fight against some power cord you have configured.

I doubt you have changed your power settings in windows, so that's probably out. But the BIOS you might also check, you can configure when fans turn on/off, some are set all the time, some when heat exceeds a certain temperature so it ramps up as it gets hotter, etc. Might also check all your fans are plugged in too.

Lastly, check the boards are entered correctly. ISA/PCI days you just slipped the card in, and that was it. More recently with video cards and the 16x PCI bus or whatever, there's a locking mechanism, so make sure the whole card is entered correctly, and fits securely, as well as if it requires external power plugs those are plugged in too (either the card itself, or fans).

If you haven't done it in a while, you might also do compressed air set at 50psi or thereabouts and give your entire system a dusting, dust collecting in heat sinks can add up.

It may come down to taking everything out, and putting it back in. But be mindful of static, that can kill any hardware as they aren't regulated for 50,000+ volts.

How old are your drives?
I get issues when they have over 10000 hours of usage, recently I had to replace my boot ssd because it gave up the ghost.

You can download CrystalDiskInfo to check on the status.

I would start by downloading a program like HWMonitor to check temps and make sure that you're not thermal throttling, all fans are running, etc.

If thermals are fine, I would double check that what WIndows reports you have for hardware is what you're actually supposed to have (e.g. Amount of RAM, video card). This should include checking Device Manager to make sure that the proper drivers are all installed.

It's also possible that the problem coincidentally happened to start when you opened your case. I would do the regular checks for viruses and malware to be safe.

If you're comfortable installing Windows and have another empty HDD or SSD available, you could always switch it out for your main drive and do a fresh install of the OS. MAKE SURE to disconnect your main drive and only have the empty one connected unless you want to risk losing data!

If things are still not working properly after those steps, a piece of hardware has likely been damaged.

I had something just like this happen to me with a gigabyte board for my 3770k, at the end it was a motherboard problem which was very odd but yeah. What specs you have? name of parts? and what parts did you remove first. maybe if we reverse this we can figure something out.

Ancient-Red-Dragon mentioned something with the OS, You can have issues arise from switching parts on a computer when using the same OS from older parts.

I had problems from SSD, HDD, Soundcard and graphic cards.

In my experience, outside of thermal throttling, "being sluggish" in general is 90% a software/OS/driver issue, not necessarily a hardware one. Believe you me, if you ever have a hardware problem, you'll know, not guess about.

It could just be a coincidence things started acting up while you swapped out components, such as maybe Windows installed a newer set of problematic drivers at the same time.

Have you tried to see if the issues you are seeing are reproducible on a fresh OS install? Just remove your main OS drive, and use a spare one to install a trial copy of Windows and test things out (you can install and use Windows without a license key, btw, perhaps a little known fact). If a bare-bones install of Windows 10 has issues, then yes, you're in deeper trouble - but somehow I doubt that will be the case.

ok ok .......

well i'm fairly certain that cooling is not the problem. i have the cpu cooled with an aio and the gpu, that i purchased actually after the problems started also has an aio of its own.
that said, when i came home today hoping that the problem would have resolved its self, i had a very weird experience. After booting up, i decided to check with a game to see how my system would react today. I fired up steam and started up Total War Warhammer 3, a fairly demanding title, while noticing a download at the same time. Starting up took forever, and in the meantime i noticed with the nvidia osd that cpu usage was at 100%. a couple of seconds later a gust of very hot air passed by but there was no audible reaction in the fan's rpm. After this, i immediately closed down the system and replaced the cpu with the another one. The cpu cooler came off very difficult, like it was vacuum pulled or something. The only time i had a similar experience was when i forgot to pull in the energy cables of the cpu cooler prior to booting up the system. The cpu cooler came of very difficult too after that uhm little incident.

The mystery with retracing my steps was actually that i had switched almost all components before trying everything at once. And nothing worked of course. Currently i switched the 15 10600k i'm using with the i5 10400f from a familymember and now it is working fine again. This is not a viable situation though so i'm forced to either continu with the 10600k again or hope that someone recognizes this particular set of problems

i did not gave windows a clean install yet. this is certainly something i can do within the next days
and before i forget. i do use a security package, norton so i'm hoping a virus will be out of the question

Aside from heat issues, one not so easy reason for sluggish performance due to hardware problems is some RAM problems like one module not inserted correctly so you are stuck using a single stick but you now have too little RAM and too little bandwidth for your game.

Really check your temperatures as you might have a cable or the protective film left between a heatsink and a processor or some such.

Also, did you remember to plug in the correct additional power to the CPU.

Also, hardware changes = uninstall and install new drivers for the motherboard and RESTART (not shut down and start again! Idiotic Windows feature....) your system and check the settings in UEFI.

Are you sure you are plugging the AIO in the right fan header? Motherboards have quite a few sometimes, but only one main header for the CPU... sometimes there are 2 main ones selectable by BIOS option, an AIO specific header (PUMP?) and a FAN0 header.

Point being, read the motherboard manual and your AIO manual and make sure you're using the right ones and that they correspond to fan curves you've set in the BIOS or utility of choice. Not all FAN headers are created equal.

it is hard to deduct if anything went wrong and what went wrong concerning the heat. I tinkered about 2 weeks ago for the last time, installing the aorus 3080 waterforce 12 gb. I had to pull some cables but in the end i think everything was done right. Also when i checked yesterday, swapping cpu's etc there was really nothing indicating a flaw
yes i'm quite sure, the only thing i can imagine is the fans returning to automatic but i don't think that would allow the cpu to get that hot. I mean for me to feel the heat would mean that the cpu would have been almost at its max temp.

still thanks though, i will update drivers and such, search for other neglects and hope this is the last time that i faced this problem

In general or specific tasks/programs?

Any given time -or- after some time elapsed?

A sudden performance fall -or- its progressive -or- bursts?

Sorry to ask too much but those details can help to pinpoint the cause

In general terms I'd suggest to pay attention to this things (They were already mentioned)
-Heat
-The PSU
-Dust
-Cables connected firmly

And I also second the others already mentioned:
Pieces fit correctly, MB, RAM, HDD, operating system, drivers, virus

Please try to prioritize them based on the details/history of your PC
If need more help, please share exact models, age, relevant recent changes, and so on

The good thing is I read you have spare parts to swap and test
A total life saver! :)

Prepare yourself with enough patience, carefulness,
follow some method and you will find the cause (or closer)
Go for it and good luck! :)

In general.

The problem appeared 3 times now. First time it was 'fixed' with a reboot
the 2d time it stayed for 2 or 3 days. fixed after multiple hardware swaps to see if i could locate either ram gpu or cpu to be problem. It ended with the described complete swap also removing other cards, network and soundblaster with no real hint as to what exactly might be the problem.
the third time the problem started after wakening up the pc and remained untill i swapped out cpu's.
A forum mod over at Tom's Hardware suggested, next to suggestions also offered by the crowd here that there might be a power delivery problem in the vrm's

this question is hard to answer actually. It seems the cpu is running with only 1 core and while the gpu is able to perform small tasks in older games quite stable its all over the place with modern titles. Just as if it falls short in something. i guess i would say progressive

How is your radiator placement? If it's below the water pump, or tubes at the top, then your AIO might be dying.

I'm not into water cooling, but I remember this video from GamersNexus about radiators' wrong placement.