Question overclocked a cpu and maybe damaged something in the process

[wolflegend615]

Hi so like the title says, I may have damaged some hardware trying to overclock my i7 9700k.

I am not looking for a fix(because I ordered new components already), I'm more of looking for a way to determine what went wrong and maybe if you guys have some advice that could help me improve my knowledge of overclocking.
so first thing first, the system was running fine a week ago, maybe minus some crashes that happened before it that made me open up my pc and start cleaning the radiator and fans because I was sure it was just over heating (it was not overclocked just dirty). so after I cleaned it from all the years of dust it was working fine for a couple of days. and then I had this brilliant idea, I wanted to close the gap between my super awesome 3080ti that I bought overpriced in the midst of inflation and my i7 9700k that is old and not exciting anymore..
so I went on youtube like any good lad in this era, and I looked for the easiest way to overclock, which is where I found this really cool and exciting piece of software, the "intel XTU"
I hopped on the bios, disabled VT-d, and then VBS (core isolation) on windows(bad idea don't ever do that) enabled X.M.P
and I began to increase the ratio by 1, and then benchmark, increase it again and benchmark. I did it to 4.9Ghz it was fine, a bit overheating, so I turned down the voltage offset till it was running fine and then I thought maybe I can do 5Ghz. but this time I used the advanced tab and like the moron that I am I looked online for what voltages people run on that cpu for 5Ghz overclock. I literally saw 1.375v and I went with that. pc ran fine, I saw increase in game fps, and I was so happy. until everytime I restarted the pc it went into bios and told me to load optimized settings, which I did because it wouldn't let me in windows if I didn't, and then I would just get back to XTU, and apply the same settings and keep playing.
also I had HWinfo open and I looked at temps the whole time I was playing, highest temps I saw on 5Ghz was 86c. but then it crashed....
so I went back to 4.9Ghz... and games kept crashing the pc or totally freezing it.. so I got a little scared and restored back all the settings. so stock settings and games just won't run longer than 30 minutes sometimes less. so I thought maybe I corrupted a system file, you know it's been hard crashing a lot and it might have done something to windows.
so I put windows 10 on a thumb drive and did a clean install of windows hoping it would fix it.... but... it didn't.
I actually used HWinfo to log everything till the pc crashed. I don't know how to add files here so if you're reading this and want the file just tell me and I'll send via email or something

EDIT: realized some specs might be in order here
CPU: intel i7 9700k
GPU: RTX 380ti 350w
motherboard: Z390 AORUS ULTRA CF , recently flushed the bios to the newest build
PSU: some corsair 750w psu, maybe it's a little short for this build ngl
RAM: maybe it doesn't matter but it's DDR4 4x8 G.skill sticks running at 3200Mhz when X.M.P enabled

 

[kgt1182]

It is recommended to overclock from the BIOS rather than from Intel XTU given the option. When XTU restores "all the settings" it might not have restored everything to default.

1.35-1.4V would be a maximum safe voltage although I doubt the 9700K would have degraded in such a short span of time, unless the voltage applied by the motherboard was much higher than reported in HWinfo. Sometimes, right after a failed overclock, default settings can also crash for the first time due to RAM "training" where subtimings are adjusted at boot.

Not all 9700K CPUs can reach 5 GHz even with a liquid cooler. It is good to set your CPU's VCore to a maximum that you are comfortable with such as 1.35V, and then set a conservative clock of maybe 4.5 GHz all core and stress test in 100 MHz increments until it crashes or overheats (~80 degrees Celcius). Then reduce the clock by 100 MHz and you should be set.

 

[wolflegend615]

It is recommended to overclock from the BIOS rather than from Intel XTU given the option. When XTU restores "all the settings" it might not have restored everything to default.

1.35-1.4V would be a maximum safe voltage although I doubt the 9700K would have degraded in such a short span of time, unless the voltage applied by the motherboard was much higher than reported in HWinfo. Sometimes, right after a failed overclock, default settings can also crash for the first time due to RAM "training" where subtimings are adjusted at boot.

Not all 9700K CPUs can reach 5 GHz even with a liquid cooler. It is good to set your CPU's VCore to a maximum that you are comfortable with such as 1.35V, and then set a conservative clock of maybe 4.5 GHz all core and stress test in 100 MHz increments until it crashes or overheats (~80 degrees Celcius). Then reduce the clock by 100 MHz and you should be set.

I understand. I have another question. what could be crashing the computer during gaming, is it the cpu I tried overclocking, the psu maybe got damaged?, or is it more likely my motherboard causes the issue?
because right now I'm writing this on the very same system we're talking about, and it appears to work fine, I watch youtube and netflix, I can chat on discord and make voice calls. and I can even game for about 20 minutes before it crashes or freezes entirely. I really don't think it's my AIO cooling solution, however that thing is 5 years old and I never reapplied the thermal paste, I assumed tho that it isn't a problem since I don't see spikes in temps. could you give me an idea how to find the cause of this problem?.
the thing I thought to do is lend a cpu to test if the system crashes, and if it does then I would know it's probably the motherboard, since I really don't think it's a psu problem then it would make sense. it's between the 2.
or maybe it's ram? how do I test my ram?
can I test the ram without stressing the cpu?