PCI Express PCIe Expansion Slots << Previous Next >> Overclocking

AMR and CNR Slots

The audio modem riser (AMR) card is a specific type of card used to fit additional cards into a compact space. In the photo below, you can see the vertical circuit board plugged into the motherboard, then a PCIe x1 card connected horizontally to it. This vertical card is a riser card. The AMR allows for analog modems and audio connectors to be used on a riser card. The communications network riser (CNR) has largely replaced the AMR, and allows for six-channel digital audio, networking functions, and other high-quality integrated audio support on a riser card. All of these riser cards are proprietary and bundled with the motherboard when originally purchased from the manufacturer. You cannot use a riser card from one manufacturer with another’s motherboard; they are not interchangeable. They were designed to allow for more expansion devices in a smaller amount of space.

VIA EPIA-M910 mini-ITX board — PCIE-03 riser card. Photo used under CC-BY license from VIA Gallery.

The central processing unit is also known as a CPU or processor. Processors come in two main architectures: 32-bit and 64-bit. We denote 32-bit processors (or applications designed for these processors) as x86. The 64-bit processors and applications are denoted as x64. You can purchase a CPU from either Intel or AMD and it could be x86 or x64, as both companies make both types. The x64 processors allow for larger file sizes, more memory, and complicated programs to run faster and more efficiently. There are three things that differentiate CPU types: 1) socket type (which CPU will fit in which socket); 2) single or multicore design; and 3) the size of its cache. While Intel and AMD are fully compatible in terms of running the Windows operating system, you must actually get the correct software for your type of CPU if you are running UNIX/Linux.

A modern processor installed on a motherboard held between two fingers.

Modern processor installed on motherboard. Copyright: cookelma/123 RF Stock Photo.

Intel has been making processors for a long time and their contemporary processors all use the land grid array (LGA) socket style. LGA uses spring-loaded “lands” that connect with the bottom of the processor and a hinged clamp mechanism to hold the processor onto the motherboard. The heat sink is then snapped into the mounting holes at the four corners of the processor socket.

Spring-loaded lands and a hinged clamp mechanism mounted on the motherboard.

LGA775 socket, prior to CPU installation. Photo used under CC-BY-NC license from Edward Cai.

Intel processors are broken into families of processors, such as the LGA 775, which contains the Pentium 4, Pentium D, Celeron, Core 2 Duo, Core 2 Quad, and Core 2 Extreme. You should be familiar with the names of the various Intel families, such as Pentium, Celeron, Core, and Sandy Bridge. If you are asked if a certain processor is Intel or AMD, you need to be able to make this determination by the name of the processor alone. All the Intel processors you are asked about in the A+ exam have something in common: two repeated digits. If you see a family name such as LGA 1156, you know it is Intel because the number “1” is repeated in the array number. LGA 1366 has a double “6.” This holds true for all the processors asked about in the A+ exam.

Common Intel land grid arrays:

LGA 775 – Pentium 4, Pentium D, Celeron, Core 2 Duo, Core 2 Quad, Core 2 Extreme
LGA 1366 – Core i7 9xx, Xeon series
LGA 1156 – Core i3, Core i5, Core i7 (not 9xx)
LGA 1155 – Sandy Bridge Core i3, Core i5, Core i7 (second-generation)

A square processor with numerous gold pins surrounding a silver square. The silver square has “Intel Celeron” imprinted on it.

Intel Celeron processor. Photo used under CC-BY-NC license from Friedemann W . W.

AMD usually uses letters in their naming convention, except for the 940 series. Note “940” does not have double repeating digits. Therefore, you can tell it is not an Intel processor and, instead, it is an AMD processor. All the other families you need to know for the exam are listed with letters: AM2, AM2+, AM3, AM3+, and FM1. AMD also uses a different socket style called the pin grid array (PGA). The pins on the back of the CPU connect to the processor socket with a zero insertion force (ZIF) mechanism. The heat sink clips onto mounting lugs on two sides of the processor instead of the four corners used by Intel. All AMD sockets are PGA, except the “F” family.

AMD processors. Photo used under CC-BY-NC-ND license from Chris Pirillo.

PCI Express PCIe Expansion Slots << Previous Next >> Overclocking