Question string of characters on SO-DIMM stickers

[Turbonium]

I have 2 new matched pairs of DDR2 RAM.

As expected, the stickers all indicate identical specifications (the only difference being the dates of manufacture, based on the date codes). However, the only difference is the following:

One pair is "FH112ZY.Z5"
The other pair is "FH112WC.8D"

Does this have to do with the batch of chips the sticks use (see here)? I know it probably doesn't matter, but I want to use the better pair of the two (I only need one pair), but I don't know which to use.

 

[Soulkeeper]

Crucial/micron likely has a pdf somewhere (one for the actual dimm another for the dram chips) which could give more details on this.
My micron dimms use a different format.

The one for my dimms says the following:
Notes:
2. All part numbers end with a two-place code (not shown) that designates component and PCB revisions.
Consult factory for current revision codes. Example: MTA18ASF4G72AZ-3G2B1.

Some of the characters could denote things like "halogen-free", week of manufacture codes, temperature ratings, etc. Even internal/secret codes.

 

[Turbonium]

I take it that it doesn't matter much either way?

By the way, the Z5 sticks have a date code of 201310 (which I figure means October 2013), while the 8D sticks have a date code of 201302 (February 2013?).

 

[Soulkeeper]

memtest86 lets you save information about the dimms like this http://sterlingdesktops.com/mem-pdfs/crucial-ecc-micron-16Gb-01.txt

Maybe it's worth seeing the week of manufacture and comparing the latencies to see if there are differences there.

 

[Turbonium]

memtest86 lets you save information about the dimms like this http://sterlingdesktops.com/mem-pdfs/crucial-ecc-micron-16Gb-01.txt

Even the one for legacy BIOS?

 

[Soulkeeper]

I'm not sure, maybe someone else can verify that.
I'd imagine you can atleast see some information about the SPD for the dimms regardless of the bios.

 

[Turbonium]

It seems the date codes are more what you suggested (I went ahead and installed the "FH112ZY.Z5" pair with the date codes "201310", and CPUID reports that the date of manufacture is week 10 of 2013).