[MemoryTen Support Center] Recently Changed Articles

What is the difference between "2-clock" and "4-clock" SDRAM?

Fri, 20 Mar 2009 21:42:10 GMT

The early SDRAM DIMM design has 2 clock inputs to drive all the SDRAM chip. This was found to be insufficient due to loading on these inputs. Some 4 clock modules will not work in systems that are designed for 2 clock, but some will. SOME 2 clock modules might not work in systems designed for 4 clocks, but then again some will.

4 clock modules are the current standard and it is unlikely to change again.

What is the performance difference between EDO DRAM and standard (Fast Page Mode) DRAM?

EDO DRAM speeds up memory transactions by as little as 5% or by as much as 25% over conventional DRAM, depending upon how much Cache you have on your motherboard. Less Cache on the motherboard will result in a larger speed increase when adding EDO DRAM. EDO eliminates a wait state between the execution of sequential-read commands from memory, giving the CPU significantly faster access to memory.

How can I recognize compliant PC100 or PC133 SDRAM memory?

Fri, 20 Mar 2009 21:41:34 GMT

A PC100 or PC133 compliant memory includes a label affixed to it which identifies the module as "PC100 compliant" or "PC133 compliant " . An attempt can be made to verify it by looking at the chip marking which should indicate "-8" or "-7.5" after the string of manufacturer part number, though this may not be entirely accurate.

What happens if my memory is not PC-100 compliant?

Fri, 20 Mar 2009 21:40:35 GMT

It means you may experience system errors in a 100mhz system because the memory's performance cannot keep up with the system requirement. The system will operate at the speed of the slowest component. For example, installing 66MHz SDRAM memory in a PC-100 system will cause the bus to operate at 66MHz, rather than the speed it was designed to operate at.

Can you tell by looking at a module if it is SDRAM, FPM, EDO etc?

Fri, 20 Mar 2009 21:40:01 GMT

SDRAM, EDO and FPM chips look similar to each other. The best way to tell the difference is to reference the part number on the chip. Most DRAM manufacturers have reference books or lists on their web sites. By looking at a memory module one can attempt to guess what it is. A general guideline is to look at the IC type and size. The EDO and FPM chips are typically packaged in SOJ form and are thicker when compared to that of the SDRAM chips which are typically packaged in slim-line TSOP form. The EDO/FPM chips typically have a marking of -60 at the end of the string of numbers and that of the SDRAM chips typically have markings of -12 -10 -8 -7.5. A SDRAM module typically has a row of the resistor or resistor arrays above the contact tabs.

Does it matter which slots I plug my new module in?

Fri, 20 Mar 2009 21:38:54 GMT

In general, you will get the best performance if you put the largest module (in megabytes) in the lowest-numbered slot. For example, if your computer comes with 32MB of removable memory and you want to add 128MB, it would be best to put the 128MB module into slot 0 and the 32MB module into slot 1.

How do I determine how much memory is currently installed in my system?

Fri, 20 Mar 2009 21:37:37 GMT

If your computer is running in a Windows environment, you can point your cursor to the "My Computer" icon and Right mouse-click on it and select "Properties." The window that pops up will have some tabs on it, one of which is labeled "General." Click on the "General" tab and you will find out how much memory your system has currently installed.

The system maximum of 4GB is not being recognized

Fri, 20 Mar 2009 21:36:47 GMT

Some systems which have a maximum of 4GB will not show a maximum of 4GB in the BIOS or Windows System Information.
Some Intel systems will not show over 3GB due to various issues such as the fact that the PCI & AGP take memory from the 4GB setup.
Because your system is not showing 4GB, does not necessarily mean that the 4GB is not working, you may have to play with your BIOS to get it to recognize 4GB total system memory.

How do I install my Dual Channel Kit?

Fri, 20 Mar 2009 21:35:39 GMT

It is critical that you install your dual channel kit properly to ensure functionality of the dual channel mode. Generally dual channel kits should be installed in like pairs in the first slot of each bank. If you are installing two kits, the second kit should be installed in the second slot of each bank. If the modules are not installed in pairs the system will not recognize the dual channel mode and will revert back to single channel mode. For further details and system specific installation instructions check your systems' owners manual.

Some systems have the memory banks staggered. For example....

DIMM1 + DIMM3 = Bank 0
DIMM2 + DIMM4 = Bank 1

Improperly configuring the installation of your DIMMs can result in a loss of performance (i.e. operate as single-channel), or system instability or failure to boot.

Again, please always check your system documentation beforehand. Make sure you understand exactly their RAM installation guidelines.

And as I always recommend, make sure the DIMM pair you are installing is an identical matched pair.

I can't find my product. What should I do?

Fri, 20 Mar 2009 21:33:38 GMT

There are 2 ways to find your product on Memoryx : -

Please use this link www.memoryx.net and the click on Scan my system. OR

Search - Type your product name or keyword phrase into the search box on the Homepage. You'll be taken to a search results page listing all of the products that things to know match your search criteria, with the ability to narrow down your results by product category. If there is only one match for your search criteria, you will be taken directly to that matching product's page.

Browse - Memoryx makes it easy to browse for your product by manufacturer. On the memoryx.net homepage you'll find an alphabetical list of product manufacturers. If you don't see your manufacturer, click on the "All Manufacturers" link at the bottom of the list. Once you select a manufacturer from the list, you'll be taken to a page listing all of that manufacturer's products - and have the ability to narrow down your results by product category.

Can I use PC133 or PC100 SDRAM in my PC that has a 66MHz front side bus?

Fri, 11 Jul 2008 23:45:09 GMT

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.

Can I use DDR PC2700 memory in my machine if it shipped with DDR2 PC2-4200?

Fri, 11 Jul 2008 23:44:40 GMT

No, actually. DDR (aka DDR1) is incompatible with DDR2 memory. DDR1's speed range from PC1600 to PC3700 while DDR2 ranges from PC2-3200 to (as of right now) PC2-6400.

DDR1 memory for a desktop has 184 pins while the DDR2 equivalent has 240 pins. Both DDR1 and DDR2 for a laptop has 200 pins, but the design is different to keep you from installing one type of memory in the other's slot (and possibly damaging the machine).

Can I use 64MB EDO SIMMs in my PC computer, how can I tell if they will work?

Fri, 11 Jul 2008 23:44:01 GMT

Here is some information to help you determine if these 64MB EDO 4K modules are compatible with your computer.

Your system must support more than 32MB per SIMM socket or more than 128MB total RAM and use an Intel TX Triton chipset or later variation.

For example, if you have 4 SIMM sockets and your system supports up to 128MB of RAM using 32MB EDO modules then these modules will not work. If that is not the case then you need to purchase max 32MB EDO SIMM.

A system that supports these EDO 4K modules will typically support at least 256MB or 64MB per SIMM socket.

Some 430TX and 440FX systems will support the 64MB EDO modules but not all, they are very particular about the organization of the modules. We try to stock modules that are most likely to work in as many different system configurations as possible. Intel 440LX and BX and later system chipsets do support these 64MB EDO modules.

All purchases come with a money back guarantee in case you run into any incompatibility issues.

Can I use 30pin SIMM and the 72pin SIMM together?

Fri, 11 Jul 2008 23:43:19 GMT

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.

Can I mix tin and gold SIMMs, my manufacturer says to only use tin or only gold?

Fri, 11 Jul 2008 23:42:53 GMT

"Nearly 99% of motherboards use Tin (Palladium Nickel) which can plate onto the noble Gold of SIMM's in a cathode-anode reaction. According to semi- conductor corrosion specialists the amount of corrosion possible can not effect the proper function of the SIMM's because of the small contact surface. If it was true the finest SIMM makers like NEC would stop production of GOLD SIMM's immediately. Indeed, Tin is a little harder to work with because it tarnishes faster. Most engineers who design SIMM's agree that gold is the best. Only Intel has claimed otherwise. Indeed, no such cases of corrosion have been reported."

Can I mix PC600 with PC800 memory in my machine?

Fri, 11 Jul 2008 23:41:59 GMT

Many motherboards will not work with this configuration, so it's recommended that you go with the exact same specifications of your original memory as possible. It might take an extra few minutes to find the information, but you'll be glad you did.

Can I mix EDO and FPM modules in my system?

Fri, 11 Jul 2008 23:41:33 GMT

A few systems support using both, but it is not recommended. Most systems require you to use all of one type or the other. If you do install both in a system that supports EDO and FPM modules then your system will operate at the slowest of the memory modes, namely FPM in this case.

Can I mix ECC and Non-ECC DIMM Module ?

Fri, 11 Jul 2008 23:40:21 GMT

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.

Can I mix different memory speeds?

Fri, 11 Jul 2008 23:39:11 GMT

You can use modules of different speeds as long as they are faster than what you already have. It is recommended to use the same speed as what is already in your system to ensure stability. If you do mix speeds, the modules will all run at the speed of your slowest modules.

Can I mix and match EDO with Fast page mode (FPM)memory?

Fri, 11 Jul 2008 23:38:36 GMT

No. Extended data out (EDO) and fast page mode (FPM) memory modules are not interchangeable. You need to match the memory that is currently in your system.

Can I mix a 128MB PC100 SDRAM DIMM with a 128MB PC133 SDRAM DIMM?

Fri, 11 Jul 2008 23:37:25 GMT

Yes,you can mix PC100 and PC133 memory in the same system. The PC133 which is a faster memory will run at the slower memory's speed (in this case PC100).

However, there are some systems that will not correctly run this memory configuration.

Can I leave in the 128MB ram that is already in my computer, or should I take it out when I install my new 512MB?

Fri, 11 Jul 2008 23:36:49 GMT

You can leave it in and it should work just fine together. Memory doesn't always have to be the same size for each slot. As long as the type matches up, they should be able to work and sync-up the speed (e.g. a PC133 module and a PC100 module in the same machine would make them both run at PC100 since it's slower for one of them, but makes them all run on the same level and be more compatible.)

Can I install an ECC DIMM on a Non-ECC motherboard?

Fri, 11 Jul 2008 23:36:06 GMT

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.

Can CAS2 and CAS3 DIMM module be mixed together?

Fri, 11 Jul 2008 23:35:01 GMT

CAS2 and CAS3 parts can be mixed. BIOS settings should reflect the CAS3 setting, as the CAS2 module will run at the CAS3 setting when it is installed with a CAS3 module.

Can a PC1600 DDR DIMM be mixed with a PC2100 DIMM ?

Fri, 11 Jul 2008 23:34:24 GMT

If you have a system with both PC1600 and PC2100 modules in it, the system will work, but it will only run at a speed of PC1600.

A system will only run at PC2100 if all the modules in it are PC2100 and the system supports PC2100.

This is similar to mixing PC133 and P100 SDR SDRAM modules in a system.

Buyer's Checklist - Make sure all your bases are covered.

Fri, 11 Jul 2008 23:32:36 GMT

Get the Right Type
Does your motherboard accept SIMMs or DIMMs?

Get the Specifics
Once you find out what type of module, make sure you're getting the right:
Type (regular vs. EDO vs. SDRAM)
Speed (measured in nanoseconds)
Parity or nonparity

Play the Math Game
Are you making the most out of your open slots and existing memory? Make sure to get the ideal amount for your empty slots, so that you never have to throw away any old modules to make room for new ones.