Monday, July 1, 2002 |
|
Feature |
|
Make CPU work faster
Mayur
OVER
the past 15 years, the power of microcomputers has increased
dramatically. When people talk about computing power, they usually mean
the speed with which the computer processes data. Therefore, more
computing speed means faster processing. The circuitary design of a CPU
determines its basic speed, but several additional factors can make
chips already designed for speed work even faster. You must already be
aware of some of these, such as CPUs, registers and the memory, cache
memory, clock speed, data bus, and math coprocessor affect a computer’s
speed.
Registers
The registers in the first PCs could hold two bytes16 bits-each.
Most CPUs sold today, for both PCs and Macintosh computers, have 32-bit
register. The size of registers, which is sometimes called the word
size, indicates the amount of data with which the computer can work at
any given time. The bigger the word size, more quickly can a computer
process a set of data. A CPU with 32-bit register can process data twice
as fast as one with 16-bit register.
RAM
The amount of RAM in a computer can have a lot of affect on the
computer’s power. More RAM means the computer can use bigger, move
powerful programs, and those programs can access bigger data files. More
RAM also can make the computer run faster. The computer does not
necessarily have to load the entire program into memory to run it, but
the more of the program it can fit into memory, the faster the program
runs. For example, with more RAM available, more of the operating system
(OS) can be loaded from the hard disk at startup. If more of the OS can
be loaded into RAM, then less files need to be swapped while the
computer is running. The hard disk is slower than RAM, so less swapping
makes for a faster computer.
Internal
clock Every microcomputer has a system clock, but the
clock’s primary purpose is not to keep the time of day. Like modem
wristwatches, the clock is driven by the piece of a quartz crystal. When
electricity is supplied, the molecules in the quartz vibrate millions of
times per second, a rate that never changes. The speed of the vibration
is determined by the thickness of the crystal. The computer uses the
vibrations of the quartz in the system clock to time its processing
operations. So faster the speed of the clock, faster is the processing
power. Today, the fastest PCs have clock speeds of more than 200 MHz.
Data
bus The data bus is an
electrical path that connects the CPU, memory and other hardware devices
on the motherboard. Actually, the bus is a group of parallel wires. The
number of wires in the bus affects the speed at which data can travel
between hardware components, just as the number of lanes on a highway
affects how long it takes people to get to their destination. Because
each wire can transfer one bit at a time, an eight-wire bus can move
eight-bits at a time, which is a full byte. A 16-bit bus can transfer
two bytes, and a 32-bit bus can transfer four bytes at a time, meaning
thereby, with a wider bus, the computer can move more data in the same
amount of time (or the same amount of data in less time).
Address
bus The address bus is a set of wires similar to the data
bus that connects the CPU and RAM and carries the memory addresses. The
reason the address bus is important is that the number of wires in it
determines the maximum number of memory addresses. If the address bus
could carry only eight bits at a time, the CPU could address only 256
bytes of RAM. Today, most CPUs have 32-bit address buses that can
address 4GB of RAM. Some of the latest models can address even more.
Cache
memory Moving data back and forth between RAM and CPU’s
register is one of the most time-consuming operations a CPU must perform
simply because RAM is much slower than the CPU. A partial solution to
this problem is to include a cache memory in CPU. Cache memory is
similar to RAM, except that it is extremely fast compared to normal
memory, and it is used in a different way. The cache speeds-up
processing by storing frequently used data or instructions in its
high-speed memory. Whenever
the CPU requests information from the RAM, the cache controller
intercepts the request and searches its own memory for the requested
information. If the information is not there, the CPU retrieves the
required data from the RAM and also sends a copy back to the cache. The
next time the CPU needs the same information, the cache finds that
information, and quickly sends it to the CPU, leaving RAM out of the
loop. The speed of cache memory is nearly equal to that of CPU.
Math
coprocessor Some computers speed up certain kind of processing by
adding a match coprocessor to the CPU. A math coprocessor is a chip that
is specially designed to handle complicated mathematical operations.
Newer CPUs have math coprocessors built in. Earlier CPUs did not have
them; so many users choose to upgrade their machines by adding them.
|