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Memory installation rules for RP7420

 
Carl Houseman
Super Advisor

Memory installation rules for RP7420

In this document:
http://docs.hp.com/en/A7025-96018/ch01s02.html

under "Valid Memory Configuration", it says:

"The DIMMs across all cells in a partition should have identical memory loaded."

What does that mean exactly? This RP7420 has 2 cell boards, the first populated with 4 x 4 GB modules, the second half-populated with 2 x 4 GB modules. I'd like to add 2 x 8 GB modules to the unpopulated quads in the 2nd board. Is that a valid configuration?
4 REPLIES 4
Prashanth.D.S
Honored Contributor

Re: Memory installation rules for RP7420

HI Carl,

Find the memory loading order for RP7420

DIMMs must be loaded in sets of two at specified locations on the cell board. Two DIMMs are called a rank, so two ranks would be equivalent to four DIMMs, three ranks would be six DIMMs, and so on. The DIMMs must be the same size in a rank. The DIMMs across all cells in a partition should have identical memory loaded.

DIMM Load Order Number of DIMMs Installed
Action Taken
DIMM Location on Cell Board
Quad Location

2 DIMMs = 1 Rank
Install First
0A and 0B
Quad 0

4 DIMMs = 2 Ranks
Add Second
1A and 1B
Quad 1

6 DIMMs = 3 Ranks
Add Third
2A and 2B
Quad 2

8 DIMMs = 4 Ranks
Add Fourth
3A and 3B
Quad 3

10 DIMMs = 5 Ranks
Add Fifth
4A and 4B
Quad 0

12 DIMMs = 6 Ranks
Add Sixth
5A and 5B
Quad 1

14 DIMMs = 7 Ranks
Add Seventh
6A and 6B
Quad 2

16 DIMMs = 8 Ranks
Add Last
7A and 7B
Quad 3

Best Regards,
Prashanth

Carl Houseman
Super Advisor

Re: Memory installation rules for RP7420

Reciting the memory ordering table from the docs doesn't really help at all.

I want this question answered (restating):

In my RP7420
- two cell boards
- one nPartition
- 4 x 4GB on cell board 1
- 2 x 4GB on cell board 2
- 2 empty quads on cell board 2

May I install 2 x 8GB modules into the 2 empty quads on cell board 2?

The documentation says I can mix DIMM sizes within a QUAD as long as the DIMMS in a single RANK are the same size.

The permitted size mixing does not seem to agree with the statement "the DIMMS across all cells in a partition should have identical memory loaded".

What is "identical" ? Same size? Same manufacturer? Same everything?

"Should" I throw away all of the 4GB modules if I wish to use any 8GB modules?

And can I take the "should" as a recommendation and not a requirement?
V.Manoharan
Valued Contributor

Re: Memory installation rules for RP7420

Hi Carl Houseman,
You can have mixed sizes of memory in different quads. But as per your requirement the 8 Gb module will not be supportable in rp7420. The below are the supported memory modules in rp7420

A6098-69101 --1GB high-density SDRAM DIMM (single DIMM)
A6098-60101 --New part for A6098-69101
A6100-69001 --2GB high-density SDRAM DIMM
A6100-67001 --New part for A6100-69001
AB322-69001 --4GB high-density SDRAM DIMM (four 1GB DIMMs)
AB322-67001 --New part for AB322-69001
A5198-69101 --512MB high-density SyncDRAM DIMM memory

Note : If you order for 8Gb memory for rp7420 you will get 2Gb * 4 Modules not single 8Gb module.

Thanks and regards
V.Manoharan
Carl Houseman
Super Advisor

Re: Memory installation rules for RP7420

I'm still looking for someone to refute the statement ""The DIMMs across all cells in a partition should have identical memory loaded."

Or at least say what that statement intended to mean. You can't have "identical" memory in all DIMMS and different sizes in a quad.

If you can't tackle that question there's no need to reply.

And when I said 8GB module I knew that A6100A consisting of 4 x 2GB DIMMS.