RAM update XW6400X workstation XQ1.88 error

[eightman]

Hello,

I have read here a post about memory problem of HP XW6400 but my problem is different. (bios 02.38 Rev. A)
I had it with 4 modules of  1GB ( Hynix DDR2 PC2-5300F 667Mhz EEC Fully Buffered RAM) with HP sticker on it
I bought 2 x 4GB modules of same Hynix (with radiator) but without HP sticker. computer don't start and only beep 5x to tell memory problem.
I bought 2 other 4Gb modules also hynix , recieved with IBM sticker. don't work.( no screen and 5 beep) . If I put 2, 4 or 1  4GB module.
If i put one original 1GB module with a 4GB , screen appear with memory error (207 - incompatible memory modules detected slot 4) on the 4GB slot.

XW6400 is made to use 4x4 GB ram so I don't understand the problem.

is there a version of XW6400 that don't support 4GB module?

thanks

[DGroves]

the xw6400 uses  PC2-5300 "Fully Buffered" ECC DDR2 SDRAM which is known as FBDIMMs which is different than normal DIMM memory

please post the memory module number of what you bought i suspect it's not "FB" dimm memory

below is a FBDIMM memory kit from amazon

https://www.amazon.com/Memory-Compatible-Workstation-Xw6400-Servers/dp/B00CXVVBF2

[eightman]

I agree, Fully Buffered" ECC DDR2 SDRAM,

my modules are HYNIX HYMP151F72CP8D5-Y5 which seems to be FB dimm...

[DGroves]

if all ram is "FB" dimms then you are not loading the ram in the correct order, each memory bank is two modules and each bank must have the same size modules you can not mix 1 and 2 gb dimms in a bank

please read the hp service guide for the xw6400 or look on the side panel for the correct load order

[eightman]

I read this manual before asking help, I first use the 4 4gb modules, then try with only 2 modules (slot 1 and 3).

Pc only start with 1Gb modules...
Even after 30 years of PC building there is always new failures to "fight"

PS there is only one CPU in this case I wonder if it could prevent system from using 4gb modules?

[DGroves]

again, i require the module part numbers see example below

https://www.newegg.com/hynix-16gb-240-pin-ddr2-sdram/p/1X5-000K-00117

[eightman]

I thought part number was HYMP151F72CP8D5-Y5, here is a pic.
I read official HP modules part numbers are 398708-061, 398708-561, and later 466463-061, I found a set of 398708-561 I could buy, but I'm still not sure it will resolve my problem.

[DGroves · Accepted solution]

4GB 4R X8     HYMP151F72CP8D5-Y5 AB-C Hynix 4GB PC2-5300 DDR2-667MHz ECC Fully Buffered CL5 240-Pin DIMM

this is a Quad Rank Memory Module <--------!!!!!!!!

the "4R" is the rank spec, you need a 4GB module that says 1R or 2R 

you can not use quad and single/dual rank modules at the same time in a 6400 and a 4GB quad rank module is not  compatible

https://www.oempcworld.com/support/SinglevsDualRAM.html

you must use single/dual rank ram

https://www.ebay.com/itm/AP12K72G4BJE6S-4GB-FBDIMM-240pin-PC2-5300-DDR2-667-for-servers-2-RANK-X-4-/...

[eightman]

Thanks for this great explanation! 👍 learn everyday, never read about rank spec restriction on the XW6400. So I will order a new set of 4 modules.