|
DADDY BOB'S COMPUTER Q & A
March 19, 2006 |
Q. While I
had my computer opened, I removed and examined the
DRAM Memory modules. They were both the same except
for one thing. One had CL-2.5, and the other had
CL-3. What is this CL mean?
A.
CL stands for CAS
(column address strobe) latency, which is the number
of clock cycles it takes before data starts to flow
after a command is received. In this case, the lower
the CL rating, the faster it will respond. In your case, the
CL-2.5 is faster than the
CL-3.0. However, your computer will only run as fast
as the "slowest link" in your system, so you can't
speed up your computer by adding memory that is
faster than your computer can use.
Now, all that
said, this
difference in speed is not really enough to be
noticeable to humans. The computer may detect the
difference, but you won't. Here's why.
Let's say your
computer has a Pentium CPU that is running at 2.4
GHz. That's equal to 2,457 MHz, 2,516,582 KHz or
2,576,980,377 Hertz. A Hertz is roughly equivalent
to one CPU clock cycle per second. This is the time
it takes for it osculate from its highest peak, through
its lowest peak, back to its highest peak again,
which is one cycle.
The time it will
take for the memory to start working after it has
received the command to do so for the CL2.5 will be
2.5 clock cycles, or .000000000097 seconds. For the
CL3 it will take 3 clock cycles or .00000000016
seconds. That's a difference of .000000000063
seconds. That's a very, very short time to a human.
To see what all
the rest of the information on a memory chip means,
you can check out the
www.crucial.com
web site, probably the best source for purchasing
memory of any kind for just about any computer.
Q. I hear a
lot about something called "Dual Core". What is Dual
Core, and is it for me?
A. A dual
core processor is one of a group of processors
called multi-core. There can be triple core, quad
core, and probably more in this line. A
multi-core processor is an integrated circuit (IC)
that has two or more processors attached. This will
enhanced performance and better handle processing
multiple tasks.
A dual core
set-up is a little like having two separate
processors installed in a computer, but since they
are both on the same chip, the power consumption is
less, and processing between them is faster.
In theory, a dual core processor should be nearly
twice as fast as a single core processor. However,
in reality, there is only about a 50% gain, making
the dual core processor about 1½ times faster than a
single core processor.
Almost all newer
computers will have multi-core processors installed
in them. However, as has always been the case, it is
not only the speed of the Central Processing Unit
(CPU) that controls the speed of a computer. The
Front Side Bus (FSB) speed is critical as is the
memory type and speed. All the components in a
computer must be match or the speed is curtailed.
Something akin to having a 500HP motor in your car
coupled to a drive train that cannot go faster than
25 MPH.
All of these
computer components have steadily increased in
performance over the years, but the one device that
is still agonizingly slow in computer terms is the
hard drive. Reading and writing from and to the hard
drive is still the big bottleneck in computer
performance.
Maybe, someday in
the not too distant future, flash memory or
something like it will replace the hard drive. Flash
memory is many hundreds of times faster than the
hard drive, and the only factor that has kept the
hard drive around for so long is its cost. Nothing
yet comes close to the very low cost per unit of
storage of the hard drive.
Today, you can
buy a 100 gigabyte (GB) hard drive for less than a
100 kilobyte (KB) cost just a few years ago. Yet the
100 GB drive has one million times more storage
space than the 100 KB drive. And, terabyte
(TB) hard drives for personal computers are on the
horizon.
