Quick question about CPUs

Hi everyone. I picked up a brand new, sealed Intel Core i5 via a local listing. The issue is that my PC freezes right during the boot sequence into macOS. I’ve already tried stripping out unnecessary components, swapping RAM slots, resetting the BIOS, and doing a clean reinstall of macOS, but nothing helps. It runs perfectly fine if I boot into Safe Mode or if I use msconfig to disable the sixth core; once I limit it to five cores, everything works flawlessly. I also experimented with different core counts in the BIOS, and it functions without any issues until that sixth core is enabled. Interestingly, I ran some Prime95 stress tests using all cores, and it didn't fail there. I know my way around hardware, but I haven't encountered anything quite like this before, so I’d appreciate any help. Thanks. 😁

Motherboard: MSI B450M motherboard
Processor: Intel Core i5
Graphics Card: R7 250 1GB
PSU: Zalman GLX 600W🙂

First things first—you really ought to try a BIOS flash. I'd suggest downloading the latest version directly from the motherboard manufacturer's website and getting that installed; it’s worth seeing if a quick update might just clear up whatever issue you're running into.

Yeah, probably the BIOS. They added support for the Intel Core i5 later on, so you'll need at least version 1301 for everything to run right...

Well, I suppose even if you're on the latest BIOS—or maybe version 1601... is it actually possible to flash it again to get it working? Or should I just roll back to an older version instead?

I honestly don't think there's much we can do at this point—it feels like you're dealing with a faulty processor or maybe a bad motherboard. If you can swing it, would it be possible to borrow a different motherboard just to test things out? It might be worth seeing if the same issue pops up...

I borrowed it, and the processor seems to run without any issues. The motherboard supports it, and I even tried reflashing the BIOS again, but nothing changed. It looks like there might be an issue with the motherboard itself. I guess there's a possibility it could work if I downgraded the BIOS to an older version?

Man, I dealt with the exact same thing. Turns out my MSI B450M motherboard just didn't support that specific chip, so maybe you're running into the same wall. Everything worked perfectly once I swapped the board out. Honestly, even if it isn't that, there’s always that tiny chance the processor itself is just dead, though I know that's super rare. If you can get your hands on some spare parts, definitely test those components

I’m willing to bet my money that the motherboard is the culprit here—it’s honestly the case about 99% of the time. I mean, isn't the processor usually the very last thing to actually give up the ghost in a PC? 😁

If he’s running it on 5 cores and everything is smooth, then what's the problem? It shouldn't hurt him at all. Honestly, I don't think you'll even notice the difference while gaming, let alone when you're actually working. Just leave it like that 😉
until you've saved up enough for a new graphics card.

It looks like I’ll have to pick up a new motherboard. It’s pretty strange because I must have refreshed the product page at least fifteen times just to double-check if it actually supported the processor, haha. Honestly, it won't change my daily experience much, but I didn't buy this thing just to run it on five cores. 😁

Thanks to everyone for the advice.