Intel – ThepHuck

Building a home lab – Part 1 – Starting with CPU, Motherboard, PCIe Lanes and Bifurcation

Before we get started, a little info about this post

At a high level, I need to install five (5) PCIe NVMe SSDs into a homelab server. In this post I cover how CPU & motherboard all play a role in how & where these PCIe cards can and should be connected. I learned that simply having slots on the motherboard doesn’t mean they’re all capable of the same things. My research was eye-opening and really helped me understand the underlying architecture of the CPU, chipset, and manufacturer-specific motherboard connectivity. It’s a lot to digest at first, but I hope this provides some insight for others to learn from. Before I forget, the info below applies to server motherboards, too, and plays a key role in dual socket boards when only a single CPU is used.

Sometimes the hardest part of any daunting task is simply starting. I got some help from Intel here, though.

Intel Nehalem EX & DDR3 Speeds

We all hate that adding DDR3 sticks to a server slows down the QPI speed (or RAM Bus for lack of a better example).

That changes with the Nehalem EX proc (and perhaps Westmere), as the CPU governs the speed. You can throw up to 16 sticks of DDR3 RAM per CPU at either 800, 978, or 1066MHz, and the governing factor is the CPU: