Dual core processors
A dual core processor combines two independent processors and the L1 cache from those processors onto a single processor chip. The benefit of a dual core processor is that it can execute multiple threads at the same time without hyperthreading because you essentially have two processors.
A dual core processor has the benefit of having two processors' core features packaged into one physical processor. The core features include pipelines and cache memory. A dual core processor can benefit from the two processors' combined L1 cache on the same chip, meaning that each of the processors in the dual core each have a block of L1 cache available. The dual core processor also has a block of shared L2 cache between the two processors in the dual core chip.
A huge benefit of being only one chip on the motherboard is that the one dual core chip draws less power than two separate processors would.
Throttling is a feature built into a lot of newer processors today and involves the CPU sensing when it is going to overheat and then reduces its speed to lower the heat to an acceptable range.
Processors that support throttling have a built-in thermal sensor (a hightech thermometer) that monitors the temperature of the processor. When the processor detects that it is going to overheat, maybe due to a fan failure, the processor drops its speed so the temperature drops to an acceptable range.
Overclocking is a big feature for PC enthusiasts and involves running a piece of hardware faster than the speed at which it is rated. A number of devices can be overclocked, such as video adapters and, of course, processors.
Warning Although you may be able to overclock the processor, it is not recommended because overclocking can result in an unstable system or even hardware failure.
The Voltage Regulator Module (VRM) is responsible for regulating the voltage that is delivered to the processor. The VRM is located on the motherboard or appears as its own device in the system and provides the correct running voltage to the processor.
Some VRMs use a jumper on the motherboard to determine how much voltage is supplied to the processor, while other VRMs sense what the processor needs on startup. Typically, VRMs on the motherboard sense what voltage the processor needs and then supply that voltage.
The term chip packaging refers to how the chip is constructed and delivered to the consumer. The chip package defines the appearance or form factor of the chip. Many chip packages have been used over the years.
The chip packages you should be familiar with are as follows:
- Dual Inline Package (DIP) chip: A rectangular chip with two rows of 20
pins. Pin 1 is located at the end of the chip that has a square notch
carved into it. It is important to identify Pin 1 because when you add a
DIP chip to the motherboard, you will have to match Pin 1 on the chip
with Pin 1 in the chip socket.
Older processors, such as the 8088 and many math co-processor chips, use the DIP chip style. Although they are no longer used for CPUs, DIP chips are still used for cache memory and BIOS chips on motherboards. They are also found on memory modules.
- Pin Grid Array (PGA) chip: One of the most popular processor chip
packages in use today, the PGA chip is a square chip that has an array of
pins filling up the shape of the chip. In general, the PGA chip uses hundreds
of pins. You can locate Pin 1 on the PGA by identifying the corner
of the PGA chip that has the corner cut off - that corner is where Pin 1 is located.
Today's implementation of the PGA chip fits into a Zero Insertion Force (ZIF) socket. The ZIF socket is ideal for upgrading processors compared to the days before ZIF sockets were used because the ZIF socket has a lever on the side of the socket that you pull up on, which raises the chip out of the socket. Because the chip is automatically raised out of the socket, it allows you to simply remove the chip out of the socket with little effort! Before ZIF sockets were used, you had to pry the chip out of the socket trying to ensure that you did not damage the chip or the pins. With the ZIF socket, after the processor is raised, you can replace the old chip with a new one. In the past, not all boards used ZIF sockets, so you had to get some special extractors to pull the chip out (carefully!).
- Single Edge Contact (SEC) chip: A chip package type that was popular with the Pentium II processors, the SEC chip is a huge cartridge surrounded by a plastic casing. The newer version, SEC2, is implemented as a card that is inserted into a slot on the motherboard and doesn't have the big plastic casing around it. It is important to stress that the SEC and SEC2 are inserted into a slot and not a socket. For more information on slots and sockets, read the next section.
In this tutorial:
- Understanding Processor Terminology
- Address bus
- Cache memory
- Math co-processor
- Dual core processors
- Identifying Socket Types
- Looking at Popular Intel Processors
- Pentium Pro
- Pentium II
- Pentium III
- Pentium 4
- Don't Forget Non-Intel Chips
- Installing a Processor
- Keeping a Processor Cool
- Installing a heat sink and fan