Question i5-8500 crashes when 4-6 cores enabled yet stable with 1-3 cores

[Ashinjuka]

I have in my possession an orphaned Dell Precision 3430 containing a hexacore i5-8500 (6C6T). I have never seen a computer behave in the following manner:

If I enable four, five, or all six cores in the BIOS the machine will not boot the Windows that came on it, a Windows install drive, or a Linux LiveCD. Windows (which I have spent the most time mucking with here) throws numerous and different blue-screen sad-face error codes when trying to boot. It's all over the place, not consistent.

If I go into the BIOS and limit the machine to using only one, two, or three cores, it will boot fine, run stable, run Prime95 for 24 hours, and stay up for days in Windows & Linux. Temps and voltage appear fine.

Unfortunately, this is the only Coffee Lake motherboard & CPU I have on-hand. Are there any tests, software diagnostic tools, or hardware tricks I can use to try to determine whether the problem lies with the CPU or with the motherboard? The cheapest 300-chipset motherboard or CPU each look to be about $50 new and I'd hate to buy one and find out the problem was the other part.

Any insights and ideas here are welcome.

 

[Kenmitch]

I'd imagine the only way to test the cpu would be dropping it in another MB and seeing if it exhibits the same behavior. I don't thing there's any way to test cpu cores when they're disabled in the bios.

 

[Markfw]

My first impression is that your PSU is not supplying enough current for the 6 cores.

 

[Ashinjuka]

I do have another SFF PSU I can try. I'll do so.

If focusing only on mobo vs CPU, wouldn't one think that it's more likely the mobo that is bad, rather than the CPU? It seems odd to me that the CPU would make it through binning and then turn out as partially bad after integration. I'd think it's much more likely to be a flawed insertion, bent pins, or just a bad board, but perhaps I'm making some unfounded assumptions.

 

[Markfw]

I do have another SFF PSU I can try. I'll do so.

If focusing only on mobo vs CPU, wouldn't one think that it's more likely the mobo that is bad, rather than the CPU? It seems odd to me that the CPU would make it through binning and then turn out as partially bad after integration. I'd think it's much more likely to be a flawed insertion, bend pins, or just a bad board, but perhaps I'm making some unfounded assumptions.

Its seems that either the PSU can't supply the power, or something on the motherboard can't supply the power.

Pretty sure its NOT the CPU.

 

[VirtualLarry]

If it's not the PSU, which it could well be, it seems to me to be a buggy BIOS somehow.

 

[escrow4]

What mobo and is the BIOS updated? Stuffed CPUs are rare. Possible sure, but rare.

 

[Ashinjuka]

It's a Dell Precision 3430 SFF, so whatever mobo comes in those. Some Dell custom OEM thing. The BIOS was whatever was the latest as of last month, 1.4.2 looks right but I'll check it again.

I have a much older Dell SFF that I hoped to try the PSU from but the connectors are different. The problem child has a 6 pin and a 4 pin going to the mobo and that's it. I tried to hook up a regular ATX PSU (the connectors seemed to fit) just for the heck of it and short the pins but it wouldn't turn on. I guess until I get a cheap mobo (hi ebay!) to try this chip in that's as far as I can go for now.

 

[Markfw]

It's a Dell Precision 3430 SFF, so whatever mobo comes in those. Some Dell custom OEM thing. The BIOS was whatever was the latest as of last month, 1.4.2 looks right but I'll check it again.

I have a much older Dell SFF that I hoped to try the PSU from but the connectors are different. The problem child has a 6 pin and a 4 pin going to the mobo and that's it. I tried to hook up a regular ATX PSU (the connectors seemed to fit) just for the heck of it and short the pins but it wouldn't turn on. I guess until I get a cheap mobo (hi ebay!) to try this chip in that's as far as I can go for now.

Dell = crap lowest quality/wattage PSUs

Their motherboards are not much better.

 

[Ashinjuka]

Trust me, I'm not a fan. I merely had this thing dumped on me and if nothing else, free parts! If I could get it working, cool, since it's small, got a ton of USB ports, and front panel USB-C. If not then I'll use the chip and ram in another build and have one last spare SATA SSD kicking around.

 

[LTC8K6]

https://downloadcenter.intel.com/download/19792/Intel-Processor-Diagnostic-Tool