Windows 8.1 BSoD - 3,1 CPU Amperage(?) Issue?

[NOTNlCE]

So, I noticed this a while back, but never thought much of it until today.

I have a Mac Pro 3,1 8 core. The machine was originally a quad core, but I threw an identical E5462 in the spare socket a few months after I purchased the machine.

A while ago, I noticed that CPU A seems to run at 10+ more amps than CPU B, though both use a normal voltage, around 1.15V. At the time of writing this, CPU A is using 1.14V and 23.27A and CPU B is using 1.17V and 14.66A under 20% load. NOW. The problem. Recently, I installed Windows 8.1 via BootCamp on a brand new 1TB WD Black drive so I could do some light gaming. Whenever I put the machine under load, (gaming, heavy benchmarking, stress testing) it BSOD's with a "WHEA_UNCORRECTABLE_ERROR" message. I have since stress tested about every component I can, specifically the GPU. I have had issues in the past with my GPU failing, but I think I can safely say that it's NOT an issue this time. And with no memory issues, that leaves only the anomaly in the CPU.

The odd part is, the system is FINE under OS X. iStat has been giving me those readings for almost a year now and I have NEVER had such a problem. The only thing that's changed, really, is the hard drive. And that's brand new, Tech Tool 7 says the thing is perfect.

Unfortunately, I cannot use Windows 7 (the obvious solution in my opinion) as it BSODs due to my Velocity Solo x1.

Any ideas here? Am I better off asking this in a Windows forum? Everything I have read has indicated that it's a hardware issue, but I spend 95% of my time in OS X and it has NEVER complained.

Thanks as always.
-N

 

[Ironjer]

So, I noticed this a while back, but never thought much of it until today.

I have a Mac Pro 3,1 8 core. The machine was originally a quad core, but I threw an identical E5462 in the spare socket a few months after I purchased the machine.

A while ago, I noticed that CPU A seems to run at 10+ more amps than CPU B, though both use a normal voltage, around 1.15V. At the time of writing this, CPU A is using 1.14V and 23.27A and CPU B is using 1.17V and 14.66A under 20% load. NOW. The problem. Recently, I installed Windows 8.1 via BootCamp on a brand new 1TB WD Black drive so I could do some light gaming. Whenever I put the machine under load, (gaming, heavy benchmarking, stress testing) it BSOD's with a "WHEA_UNCORRECTABLE_ERROR" message. I have since stress tested about every component I can, specifically the GPU. I have had issues in the past with my GPU failing, but I think I can safely say that it's NOT an issue this time. And with no memory issues, that leaves only the anomaly in the CPU.

The odd part is, the system is FINE under OS X. iStat has been giving me those readings for almost a year now and I have NEVER had such a problem. The only thing that's changed, really, is the hard drive. And that's brand new, Tech Tool 7 says the thing is perfect.

Unfortunately, I cannot use Windows 7 (the obvious solution in my opinion) as it BSODs due to my Velocity Solo x1.

Any ideas here? Am I better off asking this in a Windows forum? Everything I have read has indicated that it's a hardware issue, but I spend 95% of my time in OS X and it has NEVER complained.

Thanks as always.
-N

You must use apple service diagnostic 3S123 you will see what is the hardware problem.

Google is your best friend.

 

[brand]

I noticed that CPU A seems to run at 10+ more amps than CPU B, though both use a normal voltage, around 1.15V. At the time of writing this, CPU A is using 1.14V and 23.27A and CPU B is using 1.17V and 14.66A under 20% load.

So your saying that your Mac is plugged into a 25+ Amp circuit? I highly doubt that it is pulling 23.27Amps.

 

[NOTNlCE]

So your saying that your Mac is plugged into a 25+ Amp circuit? I highly doubt that it is pulling 23.27Amps.

That's why I'm concerned. I doubt iStat is wrong, but it's reading out those numbers. Don't think I'm an expert on iStat readings, and I'm certainly nowhere near an expert on Electrics, but that's what I'm looking at. Last time I asked this question, I was told that I should just stop looking at iStats and ignore it until I see a problem, but now I have a problem.

Ironjer, I'll go ahead and run the hardware test. Can't believe I didn't think to do that first. Thanks.

 

[hfg]

So your saying that your Mac is plugged into a 25+ Amp circuit? I highly doubt that it is pulling 23.27Amps.

That's current draw at only 1.15 volts ... about 15-25 watts average for each CPU (from a 1000 watt power supply). That is probably at idle, under full load it could be 10x that.


25 amps at 115 volt line voltage would be 2800 watts!

 

[MacVidCards]

From my days in grip/electric I can tell you that most home/small bi circuits max out at 15 Amps.

A 2K tungsten was most you could put on a single circuit. This was also the quick way to find squirrelly circuits, you'd run a stinger to what should be a different circuit 50 ft away and both lights go down at once.

 

[AidenShaw]

From my days in grip/electric I can tell you that most home/small bi circuits max out at 15 Amps.

A 2K tungsten was most you could put on a single circuit. This was also the quick way to find squirrelly circuits, you'd run a stinger to what should be a different circuit 50 ft away and both lights go down at once.

20 amp outlets are very common in new construction. You can tell the 20a outlets because of the T-shaped neutral.

 

[jjhoekstra]

If this would be happening to my MacPro I would start doing some old-fashioned hands-on hardware-error detection work:
Does the error occur with only the original CPU installed? Or with only the newer CPU installed? Does the problem reappear when the second CPU is installed back? Or when the CPUs are swapped? Is the second CPU adequately installed cooling wise? (even if the reported CPU temperature is fine, there can be tiny local hot-spots in the CPU if the installation is not done correctly) What are the amps reported if the CPUs are swapped? Does the error occur when only the minimum amount of memory is installed? Are all cables-connections clean and wel connected? Doe the error occur when another hdd is used? Etc. etc.
Another point is that the WHEA error message should report 4 parameters back, these can point to the cause. Are they visible on the BSOD?

Good luck, man this can be frustrating!

 

[jjhoekstra]

Just did some digging into the E5462. There are two different core steppings for this processor, and they differ in the errata (=hardware errors within the CPU-core). If your newer CPU is one stepping and the older one is the other, than is might be that OSX is more efficient in handling these errata. Which would explain why one OS has no problem and the other has.

See: http://www.intel.nl/content/dam/www/public/us/en/documents/specification-updates/xeon-5400-spec-update.pdf

 

[NOTNlCE]

I do believe that they have the same stepping. SLANT - same that shipped with the 3,1, was installed in the 2nd socket. On that note, is CPU A the TOP socket or the BOTTOM socket? The original CPU was installed in the BOTTOM socket and the new one in the TOP. The BSoDs seem to only be occurring NOW. I recently had to redo my Boot Camp partition, and BEFORE that happened, I did not have issues...

 

[NOTNlCE]

Can't seem to run AHT for some reason. The USB stick won't boot up, or if it is booting up, I can't see anything (possibly because I have a PC graphics card?) In positive news, I have confirmed that the issue is NOT with my Windows install. I got a DIFFERENT Windows 8.1 ISO and installed the system on a different hard drive, still BSoD'd after a bit of gaming. I am also YET to encounter an error under OS X. I'm thinking maybe it's a sign from the gods to retire the 3,1. Sigh.