2026-09-27 · class-notes, a-plus, comptia, messer, hardware, motherboard, cpu, sockets, intel, amd, server
Full class notes for A+ Core 1 3.5: Intel vs AMD sockets, installing a CPU, and multisocket server motherboards.
Class notes · Professor Messer A+ Core 1 (220-1201) · Section 3, lesson 5
Quick reference: the short version of this lesson lives in the A+ Core 1 Section 3 resource sheets. This is a fourth lesson under objective 3.5 ("install and configure motherboards, CPUs, and add-on cards"), joining Motherboard form factors, expansion slots and connections. Here the theme is compatibility: matching a board to a CPU, fitting the CPU, and what makes a server board different.
By the end of these notes you should be able to:
In the world of personal-computer CPUs there are two major companies: Intel and AMD. Both make processors that do the same job and run the same software, but there are subtle differences between the two.
The traditional shorthand is that AMD is the lower-cost option and Intel the higher-performing one, so a build chasing the lowest price might lean AMD. That description is very generalised, though, and it does not stay put: because the two compete directly, you will often find Intel offering the better-priced part in a given segment, or AMD offering the better-performing one. The "who is cheaper / who is faster" crown moves back and forth between generations.
In the real world: never buy on the old stereotype alone. Compare the specific two parts you are choosing between for the workload in front of you — the generalisation is a starting point, not a decision.
Intel and AMD processors are physically similar in size, but the connectivity on the motherboard is different for each. The CPU plugs into a socket, and Intel and AMD use different sockets. That single fact drives the core compatibility rule:
You cannot mix them: an Intel chip will not fit an AMD board, or vice versa. The CPU you choose therefore chooses the motherboard for you.
CPU brand decides the board:
Intel CPU --needs--> board with an Intel socket
AMD CPU --needs--> board with an AMD socket
Intel CPU --X--> AMD board (won't fit)
AMD CPU --X--> Intel board (won't fit)
Note (beyond this lesson): sockets also differ in style. Intel desktop sockets are LGA (Land Grid Array — the pins are in the socket, flat lands on the chip). AMD used PGA (Pin Grid Array — pins on the chip) for many years on AM4, and moved to LGA with AM5. The exam here only asks you to match brand to socket, but the LGA/PGA distinction is worth knowing for handling chips carefully.
Whichever brand you use, fitting the CPU is straightforward and, crucially, requires no force. Most sockets are zero-force designs: you rest the CPU on top of the socket in its correct orientation, close the retaining cover, and lock it down with the lever or handle provided. You should never press hard or push the chip in — if it needs force, something is misaligned.
Caution: modern sockets have delicate pins (in the socket for Intel/AM5, on the chip for older AMD). A dropped or forced CPU bends pins, which is often fatal to the board or chip. Line up the orientation marker, let it drop into place under its own weight, then close and latch.
Desktops, laptops and workstations almost always have a single processor. Servers are different: when you need far more processing power, you reach for a multisocket board — one motherboard that physically holds more than one CPU. The example board Messer shows carries two physical CPUs.
Server boards scale up the other resources to match:
Dual-socket server board (schematic):
+-------------------------------------------+
| [DIMM][DIMM][DIMM] [DIMM][DIMM][DIMM] |
| |
| +---------+ +---------+ |
| | CPU 0 | | CPU 1 | |
| +---------+ +---------+ |
| |
| [== PCIe ==] [== PCIe ==] [== PCIe ==] |
+-------------------------------------------+
Two physical CPUs, six memory slots, several
expansion slots; large board built for a rack.
Note (beyond this lesson): two things the transcript simplifies. First, dual-socket boards are frequently larger than standard ATX — variants such as E-ATX or SSI-EEB — even though they mount in the same rack chassis. Second, server RAM is usually ECC (see the Memory technologies lesson, 3.3), because a server prizes data integrity over cost.
Three requests, three answers, all from the same compatibility logic.
The through-line: decide the CPU (or CPUs) the workload needs, and the socket, RAM-slot count and form factor follow from there.
A compatibility lesson is light on direct security, but the platform choices it describes carry a defender's footnotes:
| Term | Meaning |
|---|---|
| CPU | Central Processing Unit; the main processor. |
| Intel | One of the two major PC CPU makers. |
| AMD | The other major PC CPU maker. |
| Socket | The board connector a CPU plugs into; brand-specific. |
| Compatibility rule | AMD CPU needs an AMD socket; Intel CPU an Intel socket. |
| Zero-force install | Seating a CPU with no pressure, then latching a cover. |
| Retaining lever | The handle that locks the CPU cover down. |
| LGA | Land Grid Array; pins in the socket (Intel, AMD AM5). |
| PGA | Pin Grid Array; pins on the chip (older AMD). |
| Multisocket | A board holding more than one physical CPU. |
| Server motherboard | A board with multisocket, many RAM/expansion slots, rack-fit. |
| DIMM slot | A memory slot; servers have many. |
| ECC | Error-correcting memory, usual on servers. |
| 19-inch rack | Standard rack width server boards are built to fit. |
| BMC / IPMI | Out-of-band server management controller and its protocol. |