Hi all,
I'm new to this forum (but long-time reader). I've recently bought an HP Z420 tower from E-bay, which came with a 600W PSU version, latest system BIOS, Xeon E5-1650 (v1) CPU and 64GB of RAM installed as 8 x 8GB modules, and taking up all the 8 slots from the motherboard: DIMM 1..4 towards the front of PC + DIMM 5..8 towards the rear of PC. The rear ones have that RAM cover + fan mounted on top.
All the 8 x 8GB dimm modules are PC3-10600R (aka DDR 3-1333 Mhz ECC, Unbuffered and Registered) type of RAM. They all have the same HP part/number.
But the BIOS sees only 32GB out of the 64GB total. Only the DIMM5...8 banks show memory present. No matter what combination I am trying (i.e. 1 x 8GB placed into DIMM 8 and 1 x 8GB placed into DIMM 1) the DIMM1...4 never seess any ram present. I have also interchanged the 4 x 8GB dimms from first region with the 4 from rear region. Same effect (and hinting that all 8 RAM chips are not defective).
Any ideea as to what's causing this? The E5-1650 should have no issue in accepting 64GB.
Could it be that the HP Z420 mobo is picky with PC3-10600R ram modules and wants instead PC3-12800 ??
Or could it be a bent pin in the LGA2011 socket?
If I install win7 x64, both the HP diag tool and Microsoft System Information tools both show 32GB only.
The HP Diag tool passes any RAM or CPU tests ok.
It's higly improbable for 1 LGA2011 pin to get bent with the CPU and heatsink mounted on, isn't it? So it shouldn't be the transport/shipping moving something around, is it?
Also, some HP manuals mention about some "RAM front duct" plastic HP part that should always be mounted in either a 4 x 8GB or 8 x 8GB combination. That piece is missing. Could it be that there is some mechanical contact / switch on the mobo near the DIMM1...4 region and which the bios senses that it has no cover present? But wouldn't BIOS be more explicit with this i.e. a warning message?
I have also pushed the CMOS little reset button for 1 minute - thus bios reporting CMOS settings restored to default (even though the date + time was still kept current). Hoping that the cmos/bios would "un-learn" of some previous "ram training". To no effect.
Many thanks in advance for your assistance. Not sure what to do at this stage? Should I return it? I've got it yesterday.