ESD (Electrostatic Discharge) is Static electricity . This energy is found in air surrounding us and can damage electronics components in a computer such as Harddisk drive, Floppy Disk drive , motherboard , CPU, memory modules etc.. ESD occurs when one touch an object that conduct electricity.
To protect your memory module from getting damage by ESD, always keep electronics components in AntiStatic packaging until ready to use.
CL2 parts process data a little quicker than CL3 parts in that you have to wait one less clock cycle for the initial data. However, after the first piece of data is processed, the rest of the data is processed at equal speeds. Latency only affects the initial burst of data.
Once data starts flowing, there is no effect. Bear in mind, a clock cycle for a PC100 module is 10 nanoseconds so you probably won't notice a significant performance difference.
Most systems will accept either latency part. However, there are some systems that require either CL2 or CL3 parts.
Most SDRAM is backward compatible and can run at any bus speed slower than it is rated to run.
For instance, a PC133 SDRAM DIMM is capable of running at 133MHz, 100MHz, and 66MHz. There are some older motherboards that require 66MHz SDRAM and that will not accept PC100 or PC133 SDRAM, but they are the exceptions to the rule.
All PC100 and PC133 SDRAM DIMMs that are manufacturerd by the original manufacturer such as Micron,Samsung,NEC,Toshiba are built on 6 layer Printed Circuit Boards (PCBs), except for modules build by 3rd party manufacturer especially from Taiwan which typically are 4 layers. Physically you will not be able to tell the difference between the 4 or 6 layer just by looking at the PCB board. The best way is to visit the manufacturer website for more information or call their toll free number to find out.
OEM is an acronym for "original equipment manufacturer" and OEM memory means - the memory chips and PCB boards are made by the semiconductor manufacturer themselves -and the same memory that the largest PC manufacturers worldwide such as Dell, Compaq, Apple buy for use as original equipment in their systems.
No. When adding new memory, you need to match what is already in your system. 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, a parity module will not correct the error.
You can determine if your system has parity by simply counting the number of black memory chips on each module.
Parity and ECC memory modules have a chip count divisible by 3.
Different sizes of SDRAM modules can be mixed together. You do not need to fill each memory slot with the same size module, and yes, you should be able to add a 128MB module to the existing open slot on your motherboard.
Rule of thumb, the largest module should always be placed in the first slot for best performance.
Internet browsing speed depends on several factors, including your modem connection speed, traffic on the site you're visiting, and the other components in your system.
You will probably notice the biggest improvement from additional RAM if are viewing or working with large files , such as photos and digital audio and video, or if you switch between your browser and other applications often.
The term "registered" refers to how the memory module processes signals.
Registered modules contain a register that delays all information transferred to the module by one clock cycle.
This type of memory is primarily used in servers and was designed for modules with 32 or more chips on them to help ensure that data is properly handled.
While most PCs will only accept unbuffered SDRAM, there are some that accept registered SDRAM. Keep in mind that when you install registered SDRAM, all of the modules installed in your PC must be registered because unbuffered and registered modules are not interchangeable.
If your PC has a 133MHz front side bus , you will need PC133 SDRAM.
If your PC has a 100MHz FSB, you can use PC100 or PC133 SDRAM. All PCs that accept PC100 SDRAM will also accept PC133 SDRAM; however, your memory will only run as fast as the slowest "link" in your system. If you have a 100MHz FSB or any PC100 modules installed, any PC133 modules that you install will only operate at 100MHz.
PC133 SDRAM doesn't offer any immediate benefit over PC100 SDRAM if you have a 100MHz FSB. However, if you are planning to upgrade to a system with a 133MHz FSB in the future, you may be able to use the PC133 modules you purchase now in your future system.
CAS Latency (also referred to as latency) is the amount of time it takes for your memory to respond to a command.
Specifically, it is the length of time between memory receiving a command to read data, and the first piece of data being output from memory. Latency is measured in terms of clock cycles and is often noted as CL2 (two clock cycles) or CL3 (three clock cycles).
No. PC133 memory is designed for use on systems with a 133MHz front side bus or slower. If your 200MHz front side bus is on a system with an AMD Athlon processor, you probably need PC1600 or PC2100 DDR modules
RAM and virtual memory are two different things. Virtual memory allows you to use a portion of your hard drive as though it were RAM. Because your hard drive is up to 100 times slower than your RAM, virtual memory is much slower than RAM.
When you upgrade your RAM, you may discover that you use your virtual memory less because you will now have more memory available to complete the tasks that were previously handled by your virtual memory.
There are several signs indicating it may be time to upgrade your memory.
If you see your mouse pointer turn into an hour glass for significant periods of time, if you hear your hard drive working, or if your computer seems to work more slowly than you expect, the reason is probably insufficient memory.
When the memory is full, your system transfers data to the hard drive. This is called swapping. Since the hard drive is considerably slower than DRAM memory, your system seems slower altogether
Most motherboards that do not have an ECC function within the BIOS are still able to use a module with ECC, but the module will run in non-ECC mode.
Keep in mind, there are some cases where the motherboard will not accept an ECC module, depending on the BIOS programming. The only sure-fire way to test this is to place the module in the motherboard and see if the BIOS will recognize the memory addition.
The two different types of modules (buffered/unbuffered) are not interchangeable and even use slightly different printed circuit boards (PCBs). If you try to install the wrong type, the first notch on the bottom of the module will be offset.
You can determine if the module is buffered by looking at the leads next to the first notch. If the leads are evenly spaced, the module is buffered. If the leads are not evenly spaced (a larger PCB area next to the lead) the module is unbuffered.
Buffered EDO and FPM DIMMs have a buffer logic chip that is used to distribute the load placed on the chipset and is primarily used only in servers on PC platforms. Apple computers have used primarily buffered modules until their recent G3 and G4 series computers
The general rule of thumb in deciding what type of memory you need is to look at what's already installed in your system.
To find out if you have ECC, parity, or non-parity memory, count the number of chips on the module. Divide the total number of chips by three.
If you can evenly divide the number of chips by three, the module is ECC or parity, if not, then it is a non-parity module.
So what if your system does have ECC or parity memory (the chips are evenly divisible by three), how do you know which one you have? One way is to look at the part numbers on the chips of your module. If each chip has the same part number, you have ECC.
If one chip is different, you have parity.
If you are building a PC and deciding which type to use, the following guidelines should help. 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-parity.
Using ECC decreases your PC's performance by about 2%.
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-parity SDRAM.
DDR SDRAM comes in two speeds: PC1600 and PC2100. Despite what these names imply, DDR is twice as fast as PC100, not roughly twenty times faster.
PC100 SDRAM modules have a bandwidth (the amount of data they can move) of 0.8GB/sec. Since DDR SDRAM can move data twice as fast as SDR SDRAM, 200MHz DDR (100MHz doubled) has the bandwidth of 1.6GB/sec, or 1600MB/sec.
Hence, the name PC1600. 266MHz DDR SDRAM (133MHz doubled) has the bandwidth of 2.1GB/sec and is referred to as PC2100.
SPD (serial presence detect) is a small non-volatile RAM chip attached to SDRAM modules that contains information about the memory.
This information includes the number of row addresses, number of column addresses, error detection/correction, refresh rates, data width, and the interface standard.
It also contains less important information such as the module serial number and manufacturer code. When your computer powers up, it sets the row and column settings and the timings for the module based on the information in the SPD.
SPD is required in SDRAM that is 66MHz, PC100 and PC133 compliant. Standards set by Intel and JEDEC ensure that data is entered in appropriate locations so the motherboard BIOS can understand what this data means.
The SPD standard allows greater flexibility for incorporating identification of new features and technologies on memory modules.
DDR and SDRAM can be unbuffered or registered. EDO and FPM can be buffered or unbuffered. 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 do not have a buffer but do 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.
Some systems require 3.3-volt modules, and others require 5-volt modules. The two are not interchangeable, and the different modules actually have slightly different notches so that you won't accidentally install a 5V part in a 3.3V slot or vice versa.
DIMM stands for dual inline memory module, and SIMM stands for single inline memory module. The gold or tin pins on the lower edge of the front and back of a SIMM are connected, providing a single line of communication paths between the module and the system.
The pins on a DIMM are not connected, providing two lines of communication paths between the module and the system, one in the front and one in the back.
SIMMs and DIMMs are not interchangeable; they are different sizes and they install into different types of sockets.
Extended data out (EDO) memory and synchronous dynamic random access memory (SDRAM) are two different types of memory technology. SDRAM is the newer, faster type of the two. The biggest difference between the two is that SDRAM is synchronized to the CPU clock.
Most systems accept either EDO or SDRAM, but not both.
If you have more than 256MB RAM installed, you will receive a memory failure message when you run Symantec's Norton Diagnostics. The problem is caused by a limitation of the test and does not mean that you have faulty RAM.
According to the Symantec Web site, "Norton Diagnostics cannot run a memory test on systems having more than 256MB of memory. This is a limitation of Norton Diagnostics and it is not a problem with your computer's RAM."
Symantec doesn't currently have a way to fix this problem, so your best course of action is just to ignore any error messages you receive.
You can find Symantec's description of the problem at http://service1.symantec.com/SUPPORT/nunt.nsf/docid/1999090713442709&src
No. When adding new memory, you need to match what is already in your system. ECC (error checking and correcting) 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.
You can determine if your system has ECC by simply counting the number of black memory chips on each module. ECC (and parity) memory modules have a chip count divisible by 3. Any chip count not divisible by 3 indicates a non-parity memory module.
The answer to this question will vary depending on the type of system you have. In a system with a 32-bit processor (486 for example) 30-pin SIMMs must be installed in groups of four, and a 72-pin SIMM can be installed individually. In Pentium class systems, however, you cannot use 30-pin SIMMs, and 72-pin SIMMs must be installed in pairs. You can use 30-pin and 72-pin SIMMs together if the motherboard has the sockets for them.
Synchronous graphics random access memory (SGRAM) is a type of DRAM that is designed for graphics hardware requiring high-speed throughput for applications such as 3-D rendering and full-motion video. SGRAM is often integrated into your motherboard or graphics card.
EEPROM stands for "electrically erasable, programmable, read-only memory." While data stored in DRAM is lost when the power is turned off, data stored in EEPROM can be retained when the power is turned off. EEPROM can also be erased and reprogrammed.
Though the names look similar, SDRAM and SRAM are really quite different. Static random access memory (SRAM) is usually used for the cache of a system. It is very fast and very expensive, but a relatively small amount is needed to build a cache. Cache memory was designed to improve upon the performance of the processor and the memory subsystem, and is usually located next to the processor.
Most desktops and laptops use dynamic random access memory (DRAM) for the main system memory. Synchronous DRAM (SDRAM) is a particular type of DRAM used by some systems. Other types of DRAM include fast page mode (FPM), extended data out (EDO), and double data rate (DDR or DDR SDRAM).
All SDRAM is backward compatible and can run at any bus speed slower than it is rated to run.
For example, a PC133 SDRAM DIMM is capable of running at 133MHz, 100MHz, and 66MHz. There are a few older motherboards that require 66MHz SDRAM and that will not accept PC100 or PC133 SDRAM, but they are the exceptions to the rule.
Keep in mind that your memory run will only run as fast as the slowest component installed. If you install PC100 memory on a system with a 66MHz front side bus, the memory will only run at 66MHz.