Update *** its fixed *** Unusual problem - X99 Taichi won't reboot, but will cold boot. Might be CPU

[Markfw]

So, if I power on from being brand new, it powers up. Then I save BIOS changes (date/time only) and say reboot it shuts down, and won't restart. If I pull the power cord, turn the PSU off (AX850 Corsair) wait 20 minutes, then push the power button it comes on ! The CPU is a
Intel Xeon E5-2695 v3 ES QEY6 2.2GHz Bios I upgraded to 1.5 (the latest.)

Any ideas ?

 

[Burpo]

The major issue with ES chips is that generally (unless they are later or last revision), they are often unstable since the macro code isn't finalized. Hence the reason why intel makes ES chips before mass production. Few motherboards run ES chips. If it will, usually it's with the first bios. later bios may not run those chips reliably. If it's not the final stepping (C1) that's likely the problem.

 

[Markfw]

Model F stepping 1 ext model 3F. Which is that ? BTW, working now somehow, typing from it.

 

[Burpo]

Can't find much info on ES, but QD & QE are early spec cpu's. Evidently designed for OEM's to be used in pairs. From the net; "QD and QE are paperweights."
QF & QG are final version.

Here's specs on E5 V3 product family..

https://www.intel.com/content/dam/w...cification-updates/xeon-e5-v3-spec-update.pdf

It may have just needed to heat & seat better in the socket, Fingers crossed that it's stable

 

[Shmee]

I would run some stress tests to make sure it is stable.

 

[Markfw]

I would run some stress tests to make sure it is stable.

Well, its running WCG (CPU) and F@H(GPU) both@100% for 4 hours so far, no errors.

 

[kjboughton]

Dead BIOS battery?

 

[Markfw]

Dead BIOS battery?

No, it seems OK now. Not sure.

 

[Justinus]

What uefi code would it hang on when trying to boot? I just went through 5 months of troubleshooting my x99 setup with intermittent post failures that could be described similarly to yours. (I did finally get it fixed)

 

[Markfw]

What uefi code would it hang on when trying to boot? I just went through 5 months of troubleshooting my x99 setup with intermittent post failures that could be described similarly to yours. (I did finally get it fixed)

Nothing, no power. Its like the power button was not working. But it just started working, very odd.

 

[Justinus]

Nothing, no power. Its like the power button was not working. But it just started working, very odd.

Oh! That makes it sound like something was tripping one of the protections in your PSU. Turning off the power switch for 15-20 minutes is generally the way to reset that.

Maybe your PSU is defective and tripping its own protections sometimes? Or perhaps a component is not being well behaved and tripping OCP or OVP?

 

[EXCellR8]

Bad or loose switch?

 

[LTC8K6]

Could have been one of those polyfuse protection devices that resets after a while.

http://www.mouser.com/ds/2/240/Littelfuse_PTC_LoRho_Datasheet.pdf-365270.pdf

https://en.wikipedia.org/wiki/Resettable_fuse

 

[kjboughton]

I would check to ensure you dont have an unused standoff or something similar contacting the board somewhere in the back side...