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HP Recommended

Hi, apologies if this has been answered elsewhere but I can't seem to find an answer.

 

I recently purchased a HP Z420 from eBay. This came pre-installed with 2 x 8GB DDR3 PC-10600 1333Mhz ECC sticks, installed in DIMM's 1 and 8. I have purchased a further 8GB DDR3 stick but this one is 1600 Mhz ECC. I have placed it in DIMM 3 (and every other slot) however the PC will not boot with it installed. To eliminate this stick as the problem I have removed the existing 2 x 1333 Mhz sticks and installed only the single 1600 Mhz stick, and the PC boots fine. 

 

I am advised that the issue is mixing the different speed ratings, and this would appear to be the case, even though the HP website states that mixing speeds works albeit will default to the speed of the slowest DIMM.

 

Before I go ahead and purchase more 1600 Mhz sticks (and maybe try to sell the 1333 Mhz sticks...) is this something that could be cured by changing a BIOS setting, or a firmware/chipset/BIOS update? Or is it simply not possible to mix different RAM speeds. All sticks are definitely Unbuffered ECC.

 

Thanks!

 

 

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