High CPU temps with XMP on Solved

My system: Intel 7700k ran between 4.5 to 4.7ghz on an MSi z270 board.

I've had a huge problem with CPU temperatures with XMP enabled. It was odd I would hit, depending on usage low to mid 180C temps. It didn't matter if I enabled 3200mhz XMP or the lowest setting above auto in BIOS for memory. Sure that might shave a centigrade or two but it was nothing unless I just set memory at auto where I got great CPU temps. I undervolted my CPU and spent days getting it to a very nice, very stable range. That never factored into temperatures like disabling XMP or fiddling with Mem OC did.

I was running 4x8GB Corsair 3200 and after playing Conan Exiles for a while I kept getting crashes here and there and eventually I got a blue screen that lead me to testing my memory with the built in Windows diagnostic. Sure enough I had errors. I pulled the first set of modules, re-ran the tests with both XMP and normal settings applied and it worked (thank god cuz the next set required removal of the CPU heatsink, lol). Cosair set my new set out in just days time. I plugged them in and I will say I have not run memdiag yet.... but! Running XMP on with my 4.7Ghz OC my temps have never cracked more than mid 160Cs in general use. I think I saw an 171C on a core after a week long uptime that included many runs playing Conan Exiles and PUGB and messing with my GPU OC benches.

People kept telling me the temps where due to the "overclocked memory controller" on the CPU. Well I'm not so sure. Things are sublime and I haven't had a single crash or even touched 180C on any core after a week and a half.

I only bring this up because when I was looking for reasons as to why my CPU temps would go so high with XMP enabled I got ZERO INFORMATION but found several posts over there years asking the same question. Here I found I faulty modules, those were replaced and I'm doing quite well.

One last note, I even went so far as to undervolt my memory as far as possible when I had my temps going so high, I don't have my notes on hand but my BIOS was reported 1.5V or so with XMP on and I brought those down as far as I could and got very little benefit now I don't see numbers like that at all with the new set in my 4x8GB config.