RAM question for HP Z800 Workstation

[SDH]

Well, I promised I'd get back on this project.  It worked.  To the OP:  you need to check if your Z800 has the newer boot block date or the older one.  If it has the newer one (11/10/09) you can do this also.  The Z600 version 2 newer boot block date is 1/7/10.

The 8 sticks I got have the HP holo labels, 16GB each, dual rank, 1866MHz memory speed.  ECC registered.  They are Micron, but other OEM sources for the same part numbers include Samsung and SKHynix.  Same is used in HP and Dell servers, and the sticks I chose (Micron) always seem to fit in the sockets a bit tighter.... use care to ensure that each seats fully.  I personally like to clean both sides of the contacts with DNA or IPA before inserting..  I always recycle with HP ones if I can.... they are binned to a higher spec reportedly.  Careful searching is in order, and I would not mix and match sticks from different OEM vendors although that might be just fine as long as each has the HP label.

The concept here is that the memory controller  in the Z600 v2 can down-regulate these Z620 v2 HP-certified sticks to the slower speed of the Z600 v2 workstation and processors.  The Z600s I've built up are only the version 2 (with the later boot block date we've gone over here).  This will not work on a version 1 Z600, or on any Z400, I believe.  I tested this same concept with 8GB 1866 MHz ECC buffered sticks earlier in the Z620 v2 and the Z600 v2, also with success.  Here are specs for the version 2 Z600 builds I've done, one optimized for speed and cores, and the other for raw speed with fewer cores:

Two X5672 3.20 GHz QC, 95W 1333 MHz, 6.4 GT/s QPI support
Single sSpec code of SLBYK, dual Passmark CPU score = 10321 with
Single Thread Rating = 1451. eBay price 1/20 about $10.00 USD
each from A+ US sellers.

Two X5675 3.06 GHz 6C, 95W 1333 MHz, 6.4 GT/s QPI support
Single sSpec code of SLBYL, dual Passmark CPU score = 12408 with
Single Thread Rating = 1416. eBay price 1/20 about $25.00 USD
each from A+ US sellers.

Here's the QuickSpecs for memory from HP, version 6, and these have been hard to find but are valuable to have.  I've posted their links here previously:

Here are the two Properties pages from the two workstatons.... the Z620 v2 and the Z600 v2 with the memory loaded:

Finally, here is the HP memory diagnostics test results for the Z600..... took some time, but this is a good test suite from HP that I have used for years: