Chipset
This line tells you what kind of chipset your motherboard
uses. Your chipset enables many of the devices in your computer
(processor, memory, keyboard, mouse, etc.) to communicate
with one another. Unlike processors and memory, chipsets are
an integral part of a motherboard and generally cannot be
upgraded.
Accepts
PC133 SDRAM
This line tells you whether or not your system will accept
PC133 synchronous dynamic random access memory (SDRAM). SDRAM
delivers bursts of data at very high speeds using an interface
that is synchronized to the CPU clock. PC133 SDRAM meets Intel's
requirements for use with 133MHz motherboards.
In
general, PC133 SDRAM can also be used with a 100MHz or 66MHz
front side bus; however, your memory will only operate as
fast as the slowest "link" in your system. For example,
if you install a PC133 module in a system with a 100MHz FSB
or in a system containing a 100MHz module, the PC133 module
will operate at 100MHz.
Accepts
SDRAM 100MHZ
This line tells you whether or not your system will accept
100MHz synchronous dynamic random access memory (SDRAM). SDRAM
delivers bursts of data at very high speeds using an interface
that is synchronized to the CPU clock. PC100 SDRAM is a particular
type of 100MHz SDRAM that meets Intel's requirements for use
with 100MHz motherboards.
In
general, 100MHz SDRAM can also be used with a 66MHz front
side bus; however, your memory will only operate as fast as
the slowest "link" in your system. For example,
if you install a PC100 module in a system with a 66MHz FSB
or in a system containing a 66MHz module, the PC100 module
will operate at 66MHz.
Accepts
SDRAM 66MHZ
This line tells you whether or not your system will accept
66MHz synchronous dynamic random access memory (SDRAM). SDRAM
delivers bursts of data at very high speeds using an interface
that is synchronized to the CPU clock. 66MHz SDRAM is used
in systems that have a 66MHz front side bus.
Accepts
Registered SDRAM
This line tells you whether or not your system will accept
registered SDRAM. Registered modules contain a register that
delays all information transferred to the module by one clock
cycle. Like buffered modules, registered modules are typically
used only in servers and other mission-critical systems where
it is extremely important that the data is properly handled.
Accepts
EDO
This line tells you whether or not your system will accept
extended data out (EDO) memory. Enhancements its addressing
system allow EDO to operate 10 to 15% faster than FPM; however,
it is not as fast as SDRAM.
Accepts
Fast Page Mode
This line tells you whether or not your system will accept
fast page mode (FPM) memory. FPM is the oldest type of memory
that Crucial sells. In the FPM scheme, information from the
same row of DRAM can be accessed an infinite number of times
after supplying the row address only once.
Max
EDO/FPM
This line tells you the maximum amount of EDO or FPM memory
(in megabytes) that your motherboard will recognize. The total
memory on all the modules installed in your system cannot
exceed this amount.
Accepts
DDR
This line tells you whether or not your system will accept
double data rate (DDR) SDRAM. DDR SDRAM is the most recent
addition to Crucial Technology's memory offerings. It reads
information on both the rising and falling edge of the CPU's
clock cycle, roughly doubling the speed of memory processing
over standard SDRAM.
PC1600
DDR SDRAM is used in systems with a 100MHz front side bus.
PC2100 DDR SDRAM is used in systems with a 133MHz front side
bus.
Accepts
ECC
This line tells you if your motherboard will accept error
checking and correcting (ECC) modules. ECC modules have an
extra chip that detects if the data was correctly read or
written by the memory module. If the data wasn't properly
written, the extra chip will correct it in many cases (depending
on the type of error). Non-ECC (also called non-parity) modules
do not have this error-detecting feature.
If
you plan to use your system as a server or a similar mission-critical
type machine, it is to your advantage to use ECC. If you plan
to use your PC for regular home, office, or gaming applications,
you are better off with non-ECC. Current technology DRAM is
very stable and memory errors are rare, so unless you have
a need for ECC, you are better served with non-ECC SDRAM or
DDR SDRAM.
Accepts
Parity
This line tells you if your motherboard will accept parity
modules. Parity modules have an extra chip that detects if
data was correctly read or written by the memory module, depending
on the type of error. However, unlike an ECC module, a parity
module will not correct the error.
If
you plan to use your system as a server or a similar mission
critical type machine, it is to your advantage to use parity.
If you plan to use your PC for regular home, office, or gaming
applications, you are better off with non-parity. Current
technology DRAM is very stable and memory errors are rare,
so unless you have a need for parity, you are better served
with non-parity DRAM.
Accepts
RDRAM (Rambus)
This line tells you if your motherboard will accept Rambus
(RDRAM) memory. Rambus is a proprietary memory of Rambus Inc.,
and manufacturers who produce it are required to pay a royalty.
Rambus and SDRAM modules are not interchangeable and do not
fit into the same size slots.
DIMM
Socket Count
This line tells you how many dual inline memory modules (DIMMs)
can be installed in your system at once. A DIMM consists of
a number of memory components (usually black) that are attached
to a printed circuit board (usually green). The gold or tin
pins on the bottom of the DIMM provide a connection between
the module and a socket on a larger printed circuit board.
The pins on the front and back of a DIMM are not connected,
providing two lines of communication paths between the module
and the system.
DIMMs
come in several sizes. 168-pin DIMMs, the most common size
for PCs, are approximately 5.375" long and 1.375"
high. 100-pin DIMMs, the most common size for printers, are
approximately 3.5" long and 1.25" high. 184-pin
DIMMs, used for DDR SDRAM, are approximately 5.375" long
and 1.375" high. While 184-pin DIMMs and 168-pin DIMMs
are about the same size, 184-pin DIMMs have only one notch
within the row of pins while the 168-pin DIMMs have two notches.
Sockets
per DIMM Bank
This line tells you how many DIMMs must be installed at the
same time. In most cases, DIMMs are installed individually.
However, if there were two sockets per bank, you would need
to install two modules at the same time. In this scenario,
if you wanted to add 64MB, you would need to purchase two
32MB modules and install them together.
72-pin
SIMM Socket Count
This line tells you how many 72-pin single inline memory modules
(SIMMs) can be installed in your system. A SIMM consists of
a number of memory components (usually black) that are attached
to a printed circuit board (usually green). The gold or tin
pins on the bottom of the SIMM provide a connection between
the module and a socket on a larger printed circuit board.
The pins on the front and back of a SIMM are connected, providing
a single line of communication paths between the module and
the system.
Each
72-pin SIMM provides a 32-bit data path, so they can be installed
singly in 32-bit systems (486 models) but must be installed
in pairs in 64-bit systems (Pentium and Athlon models). 72-pin
SIMMs are approximately 4.25" long and 1" high,
though the heights may vary. They have one notch on the bottom
left and one notch in the center of the module.
Sockets
per 72-pin SIMM Bank
This line tells you how many 72-pin SIMMs must be installed
at the same time in your system. In general, they can be installed
singly in 32-bit systems (486 models) but must be installed
in pairs in 64-bit systems (Pentium and Athlon models). If
you have two sockets per bank, you would need to install two
modules at the same time. In this scenario, if you wanted
to add 64MB, you would need to purchase two 32MB modules and
install them together.
30-pin
SIMM Socket Count
This line tells you how many 30-pin single inline memory modules
(SIMMs) can be installed in your system. A SIMM consists of
a number of memory components (usually black) that are attached
to a printed circuit board (usually green). The gold or tin
pins on the bottom of the SIMM provide a connection between
the module and a socket on a larger printed circuit board.
The pins on the front and back of a SIMM are connected, providing
a single line of communication paths between the module and
the system.
Each
30-pin SIMM provides an 8-bit data path, so they must be installed
in banks of 4 in order to communicate with 32-bit systems
(such as 486 models). All 30-pin SIMMs use FPM memory technology.
30-pin SIMMs are approximately 3.5" long and .75"
high, though the heights may vary. They have a single notch
on the bottom left to ensure that they are installed correctly.
Sockets
per 30-pin SIMM Bank
This line tells you how many 30-pin SIMMs must be installed
at the same time in your system. In general, 30-pin SIMMs
are installed in banks of 4. That means that if you wanted
to add 64MB, you would need to purchase four 16MB modules
and install them together.
Buffering
This line tells you whether your system takes buffered, unbuffered,
or registered modules. Unbuffered modules are the most common.
In unbuffered memory, the chipset controller deals directly
with the memory. There is nothing between the chipset and
the memory as they communicate. Buffered modules contain a
buffer to help the chipset cope with the large electrical
load required when the system has a lot of memory. Registered
modules are unbuffered modules that contain a register that
delays all information transferred to the module by one clock
cycle. Buffered and registered modules are typically used
only in servers and other mission-critical systems where it
is extremely important that the data is properly handled.
DDR
and SDRAM modules can be registered or unbuffered; EDO and
FPM modules can be buffered or unbuffered.
Max
Unbuffered SDRAM
This line tells you the maximum amount of unbuffered memory
(in megabytes) that your motherboard will recognize. The total
of all the modules installed in your system cannot exceed
this amount. In unbuffered SDRAM, the chipset controller deals
directly with the memory. There is nothing between the chipset
and the memory as they communicate.
Max
Registered SDRAM
This line tells you the maximum amount of registered memory
(in megabytes) that your motherboard will recognize. The total
of all the modules installed in your system cannot exceed
this amount. Registered modules contain a register that delays
all information transferred to the module by one clock cycle.
is usually done on modules with a lot of memory to help ensure
that the data is properly handled.
CL=3,
CL=2, and CL=2, 2-clock
In our Memory Selector, the CAS latency of our parts is designated
with "CL=3," "CL=2," or "CL=2, 2-clock."
(You may see this written elsewhere as "CL2, etc."
or "CAS=2, CAS=3, etc.") CAS latency is the amount
of time it takes for your memory to respond to a command.
It only affects the initial burst of data. Once data starts
flowing, latency has no effect.
Latency
is measured in terms of clock cycles. For example, a CL=2
part requires two clock cycles to respond, while a CL=3 part
requires three clock cycles. Thus, CL=2 parts complete the
initial data access a little more quickly than CL=3 parts.
However, a clock cycle for a systems with a 100MHz front side
bus is only 10 nanoseconds (10 billionths of a second), so
you probably won't be able to tell the difference between
a CL=2 and a CL=3 part.
Most
systems will accept either part; however, some systems require
one or the other. These requirements are built into our Memory
Selector.
