Installing 4 memory modules in a dual-socket server motherboard with 16 memory slots

Question

I have a server board with two Xeon E5-2600 v3 processors and 16 memory slots. I ordered two quad-channel memory kits, but only one of them has arrived, so I only have four memory modules. Which slots should I install the memory modules into? The slots are labeled as follows:

p1a1 p1a2 p1b1 p1b2 p1c1 p1c2 p1d1 p1d2 p2a1 p2a2 p2b1 p2b2 p2c1 p2c2 p2d1 p2d2

Answer 1

Here's what the memory slot labels mean:

• The first two characters p1 and p2 refer to the processor to which the slot belongs. Each processor can access each others' memory but performance will be significantly degraded if accessing memory on a slot for a different processor. For more information, see the Wikipedia article on non-uniform memory access.
• The third character, which may be a, b, c, or d, refers to each of the four memory channels on each processor. Type E, EP, and EX processors starting from the Sandy Bridge generation (including your Haswell-EP processors) support quad-channel memory.
• The fourth character refers to the two memory slots for each memory channel. For optimal performance, you should populate all memory channels with one module each first before adding additional modules on each channel.

As you don't presently have enough memory modules to enable quad-channel mode for both processors, you should install two memory modules, using channels a and b, for each processor. The processors will fall back to dual-channel mode.

Therefore, you should install the modules in p1a1, p1b1, p2a1, and p2b1. When you get the other four memory modules, install them in p1c1, p1d1, p2c1, and p2d1.