TL;DR: My 2700x went from working great to being a dud, seemingly overnight. In Cinebench went from getting a score of around ~1800 bone stock and just under 2000 undervolted to around 1500 stock and 1700 undervolted seemingly overnight.
I can not figure this out. I'm running a Ryzen 7 2700x on a Asus Crosshair Hero VII with 2x8gb G. Skill Trident 3600c15. I had the system tuned perfectly with a -0.05v offset undervolt with PBO/XFR that would boost the cpu to 4.45 ghz single sore and ddr4 timings at 3600c14 stable. The cpu is watercooled with a 280mm radiator and usually idled at 30 degrees and only ever hit around 70 degrees after a good amount of time doing while stress testing. My settings were not at all aggressive, all voltages were well within safe margins and temperatures for CPU, VRMs and memory were all exceptional even while running intel burn test or prime 95.
Booting up yesterday, the pc was sluggish and i noticed idle temps were upto around 40-45 degrees and the cpu temperature would spike often and would instantly shoot to 70-75 degrees under load, as opposed to gradually increasing under load as usual. Memory and VRM temps were still fine. The cpu would still boost to 4.45ghz and is still within the same voltages as before, but my cinebench scores were way down to around 1650-1700. The computer is generally a lot more sluggish with longer load times. I tried resetting the bios to optimized defaults with XMP enabled and my cinebench scores went to around 1450-1500.
Here's what I've tried doing:
-Unplugging everything from the motherboard except CPU, Ram and main boot drive
-Remounting the AIO cooler 3 times, the pump works properly and EVGA flow control detects the pump and shows it going at full speed, i am running noctua 3000rpm industrial fans on all my radiators, even at 100% pump and 100% fan the cpu temps (tdie) jumped right to 70-75 under load
-Mounting another 360mm aio twice, i know this one is working on another PC without issues, no improvement in temps
-Mounting the stock wraith prism cooler 3 times, slightly higher temps and worse performance then with the water coolers, but less points of failure, so i dont think its a cooling issue
-With each mount I tried different thermal pastes (Noctua Nt-H1 or Thermaltake TG-7), i didnt notice any issues with contact based on the paste left behind on the cooler or cpu afterwards
-Checking the backplate to make sure nothing is between it and the motherboard
-Reseating the CPU
-Reseating the ram 3 times
-Running ram at lower frequencies/timings
-Removing the motherboard from the case and running the motherboard from a cardboard box
-Updated to latest chipset drivers in windows
-Using another power supply
-Clearing CMOS and reflashing the motherboard BIOS multiple times
Nothing I have done is getting temperatures or benchmark performance back to where they were before. Is there any other steps I am overlooking or anything else i should check? I don't think this is a windows issue since the temperatures are wonky in the bios as well, whereas that wasnt the case before. I have no idea what the point of failure is here but I'm starting to think its either the CPU or the motherboard. Unfortunately I don't have another CPU/motherboard to test it out.
Thanks in advance, any help is appreciated!