A+ Essentials Study Guide
1.0 Personal Computer Components
1.1 Identify the fundamental principles of using personal
CPU chips (e.g. AMD, Intel)
Hyperthreading (Hyper-Threading) Technology enables a single
physical processor to execute multiple threads (instruction streams)
simultaneously, resulting in improved performance.
For example, in Intel® Xeon™ family of processors each physical processor
act as two logical processors for the operating system. The two logical
processors will still share the same execution resources of the processor
core. Hyperthreading was added to Pentium 4 processors afterwards. The
advantages of HyperThreading are support for multi-threaded code, allowing
multiple threads to run simultaneously, improved reaction and response times,
and the increased number of users a server can support.
Using conventional processing, the processor used to execute
only one task (or process) at a given time. If the given process is busy
fetching instructions from memory, the processor simply used to wait for
instructions to be fetched from memory. Using Hyperthreading, the processor
can execute two or more threads simultaneously, and the wastage of processor
time is minimized.
Note that the applications need to be
written to comply with Hyper-threading to use the improved performance.
A Hyper-Threaded intel processor has "H T" letters inscribed as
A dual-core processor consists of two complete
execution cores in one physical processor , both running at the same
frequency. Both cores share the same packaging and the same
interface with the chipset and memory. Multi-core is similar to
dual-core, but allows for more than two separate processors. Here
too, the programs must be written to use multi-processing to take
advantage of Dual-Core technology.
A Dual-core processor may also implement
Hyper-threading to improve performance. The primary difference
between Dual-core and Hyper-threading is that in the former, the
entire processor is duplicated including execution core.
Hyper-threading doesn't duplicate execution core of the processor,
though the Operating System sees HT processor as two separate
throttling refers to slowing down of the processor when required.
For example, if the CPU is overheated, you may want to slow down the
CPU clock to reduce power consumed by the CPU, and thereby avoiding
any damage to the Processor due to overheat.
MMX is designed to accelerate multimedia and communications applications.
This is done through a set of Micro code instructions which are built
into microprocessors to enable them to handle common multimedia operations
like DSP (Digital Signal Processing).
Multimedia applications such as graphics, video, games, and music files can
be benefitted by using MMX technology. MMX technology can only be used by
software that is written specifically to use the MMX instructions. These
applications are referred to as MMX enabled.
Overclocking is the term used to gain more performance by
running the CPU or memory or any other computer component at a speed higher than
that specified by the manufacturer.
Typically, CPU/memory vendors test the components at rated conditions for
proper functionality. For example, if the rated temperature is 40C, the actual
ambient temperature may be much less than 40C. This gives room for running the
CPU at a higher clock-rate under ambient conditions. A processor rated at
2.4GHz might be overclocked to 2.6GHz, while memory rated at 200MHz might be
pushed to 220MHz or higher. The extra speed results in higher performance by
the processor and/or memory in a given time period, increasing the overall
computing power of the PC.
Use of Cache memory: Usually, the main memory is
made up of DRAM (such as SDRAM), which is very slow. Cache (pronounced as Cash) is
made up of high speed RAM (such as SRAM), and is quite fast. Cache
memory works as intermediary, where the instructions are stored for
execution after being fetching from the main memory or hard disk. If
a particular instruction is not available in Cache for execution, it
is called a Cache Miss, and corresponding code block is fetched from
the main memory/hard disk and stored in the Cache. The
implementation of Cache memory significantly reduces the memory
access time for the processor, and expedites instruction execution
There are two types of cache memory.
L1 cache typically resides internal to the
processor, and L2 cache usually sits outside the CPU chip (but some
recent CPUs have L2 built within the chip). Cache normally utilizes high speed RAM such as SRAM.
A typical L1 cache is 256Kb and a typical L2 cache is 1MB.
Disk Cache: Disk caching is similar to Cache memory,
but instead of using high-speed SRAM, a disk cache uses conventional
main memory. The most recently accessed data from the disk is stored
in a memory buffer. When a program needs to access data from the
disk, it first checks the disk cache to see if the data is there.
Disk caching can improve the performance of applications
significantly, because accessing data in RAM is much faster than
accessing a byte on a hard disk.
Short for Voltage Regulator Module, it is installed on a
motherboard to regulate the voltage fed to the microprocessor. Nearly all
motherboards have either a built-in voltage regulator or a VRM.
System Properties dialog box displays basic information about your
computer's processor speed. However, the value for the processor
speed in this dialog box may differ slightly from the manufacturer's
The value that is listed in the System Properties
dialog box refers to the current speed of the CPU and not the
processor's maximum speed.
It is basically the
addressable memory space of a CPU. A 32-bit CPU can address 2^32 or 4GB of
memory space, whereas a 64-bit CPU can address 2^64 bits of memory space, which
is huge. Note that the OS also must support 64-bit functionality to use 64-bit
hardware. The AMD Athlon 64 line, the Intel Core 2 Duo, and some Intel Pentium
CPUs are capable of running a 64-bit OS.
Windows XP and Vista are available in both 32 bit and 64 bit
operating systems. Old 16-bit software, supported under regular 32-bit XP,
doesn't work under XP x64. 32-bit applications run under Windows XP x64 (64-bit
version of Windows XP) but use special mode. However, 32-bit applications will
not be using performance gains associated with 64-bit system. On the other hand,
32 bit XP OS can support 16-bit software. Driver support is also a big issue
with 64-bit OS. Most of the peripheral manufacturers are yet to develop drivers
for 64-bit OS.
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