RAM arrangement, 2 different speeds

[InvisibleMan]

Computer: Intel Xeon CPU E5-1607 @ 3.00 GHz, 16 GB RAM, Win 7 spak 1, 64-bit

I have 8 slots for memory arranged in 2 banks: slots 1-4 in one bank, 5-8 in the other. My computer arrived from the manufacturer with 4 identical chips, one each in slots 1, 3, 5 and 7. I've recently acquired 4 more chips, the same size (2 GB), but a faster speed. To be clear, I have 8 chips, all 2 GB, 4 each of  2 different speeds which we can call speeds A and B.

What is the best arrangement?

Currently I have the memory in this order in the 8 slots:  A B A B,  A B A B

Is a better arrangement AAAA BBBB? Or something unlikely (AA BB, AA BB)?

[Crucial_YogiH]

Hi InvisibleMan,

Thanks for contacting us today. We would be happy to help find the best way to install the RAM. What's the make and model of your motherboard? Thanks in advance for this information. 

[InvisibleMan]

Hewlett-Packard 1589. Intel Sandy Bridge-E (Rev 07) Chipset.

[Crucial_YogiH]

I tried pulling up this information and the specs you gave in the previous post and it pulls up the HP Z420 Workstation. Does this sound familiar? Thanks! 

[InvisibleMan]

Exactly correct.

[Crucial_YogiH · Accepted solution]

Thanks InvisibleMan. It appears that HP has a configuration guide that can be found here.  I would put the faster memory modules together in the first bank and the slower in the second bank. Please let me know if there is anything else we can help you with. 

[InvisibleMan]

Looking at the White Paper from HP, I agree with your recommendation if I redefine how the banks are numbered.

My original numbering scheme had 1-4 in one bank and physically contiguous, and 5-8 in the second bank and also physically contiguous. However, HP defines the bank differently, with bank 1 (the black slots), divided across the 2 physically separate banks, that is, in what I defined as banks 1, 3, 5 and 7. In reality, the 4 black slots are numbered 1, 3, 2, 4. The coloring scheme has each 4-pack of slots alternating black and white. I hope that's clear. If not, the HP paper you referenced does a better job.

Solution: Put the higher speed DIMMs in slots 1-4, as HP numbers them, and then the lower speed DIMMs in slots 5-8, the white slots on the board.

Thanks for your help. I'll mark this one as solved.