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Z840 workstation
Microsoft Windows 10 (64-bit)

Upgraded to 2nd intel E5-2650 v4.  Workstation will only boot with 1 memory module in CPU 0.  Bios recognizes both processors, but adding memory to CPU 0 causes no boot 5 beep/red led error on restart.  
This is contrary to Hp technical data and very frustrating.  Noted channel 0 memory error but do not know how to  fix.  Having trouble reflashing same version of bios as a possible fix.

All suggestion very much appreciated.

HP Recommended

first of all STOP TRYING TO FLASH THE BIOS!!~!,.....why people think a bios flash will cure anything escapes me!


all you will do flashing the bios is nothing at best and bricking the system at worst


next READ the documentation HP makes available for the z840, documentation includes directions/details on which memory to use and how to install said memory in the correct order along with troubleshooting steps


http://h10032.www1.hp.com/ctg/Manual/c04823811  (page 68)




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Perhaps this was tried, but there must be at least one RAM module in the 2nd CPU riser to boot properly with more than one module. A dual processor system will boot on only one module to allow diagnosing problems and setup.  A single CPU system can boot and run on one module. See the example z620 listed below that was changed from a single to dual processor.


As an aside, dual CPU systems benefit from a balanced configuration of RAM; an  equal quantity  for each processor of identical specification- consider always using HP part no.-labeled RAM as It's been tested by HP. The correct placement in the proper slot configuration is also an advantage.


The last office dual CPU system:


HP z620_1 (Original) Xeon E5-1620 (4-core @ 3.6 /3.8GHz) / 8GB (1X 8GB DDR3-1333) / AMD Firepro V5900 (2GB) / Seagate Barracuda 750GB + Samsung 500GB + WD 500GB
[ Passmark System Rating= 2408 / CPU= 8361 / 2D= 846 / 3D = 1613 / Mem =1584 / Disk = 574 ] 7.13.16


HP z620_1 (Rev 5) 2X Xeon E5-2690 (8-core @ 2.9 /3.8GHz) / 64GB (4X 8GB + 4X 8GB HP DDR3-1600) / Quadro K2200 (4GB) / Samsung 850 EVO 250GB + Seagate Constellation ES.3 1TB / 800W > Windows 7 Professional 64-bit > HP 2711x (1920 X 1080)
[ Passmark System Rating= 5675 / CPU= 22625 / 2D= 815 / 3D = 3580 / Mem = 2522 / Disk = 12640 ] 9.25.16 Single Thread Mark = 1903


Let us know how you progress.




HP z620_2 (2017) (R7) > Xeon E5-1680 v2 (8C@ 4.3GHz) / z420 Liquid Cooling / 64GB (HP/Samsung 8X 8GB DDR3-1866 ECC registered) / Quadro P2000 5GB _ GTX 1070 Ti 8GB / HP Z Turbo Drive M.2 256GB AHCI + Samsung 970 EVO M.2 NVMe 500GB + HGST 7K6000 4TB + HP/HGST Enterprise 6TB / Focusrite Scarlett 2i4 sound interface + 2X Mackie MR824 / 825W PSU / Windows 7 Prof.’l 64-bit (HP OEM) > 2X Dell Ultrasharp U2715H (2560 X 1440)

[ Passmark Rating = 6280 / CPU rating = 17178 / 2D = 819 / 3D= 12629 / Mem = 3002 / Disk = 13751 / Single Thread Mark = 2368 [10.23.18]

HP z420_3: (2015) (R11) Xeon E5-1650 v2 (6C@ 4.3GHz) / z420 Liquid cooling / 64GB (HP/Samsung 8X 8GB DDR3-1866 ECC registered) / NVIDIA GeForce GTX 1060 6GB/ HP/LSI 9212-4i > Samsung 860 EVO 500GB + HGST 4TB / ASUS Essence STX + Logitech z2300 2.1 / 600W PSU > Windows 7 Professional 64-bit (HP OEM ) > Samsung 40" 4K

[Passmark System Rating: = 5644 / CPU = 15293 / 2D = 847 / 3D = 10953 / Mem = 2997 Disk = 4858 /Single Thread Mark = 2384 [6.27.19

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Thank you so much for your help.


I got it to boot with one 16gb stick in each processors 1st memory channel.

I have 3x 16gb (2rx4).

I have the following single rank memory of the same specs.

4 x 8gb (single rank)

2x 4gb (single rank)


I have tried to following all instructions in adding 2nd cpu and memory.  It is my understanding that either processor should accept two of the same ranked and sized memory in each of the 4 channels.   I am trying to add the 3rd 16gb to cpu 0 to match; so that is 16 gb in slot one and 16 gb in the outermost slots.  


Also, fans seem to be on high all the time, but that is not the real issue.  Can use the odd lot of ram, (yes, it all ecc reg ram 2400T and has hp tags on it.


Any suggestions appreciated.  



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Thank you for your help.  I have tried to follow all the guidance, including conflicts in the various documentation.

I will go over your link again and see what I am missing.


thanks for your reply, all help appreciated.


HP Recommended

Hi Jon, I have a similar issue on a few different Z840’s. Did you get anywhere with this? 

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